AUGUSTA — A proposal to expand the state’s high school basketball world from four classes to five beginning next season received some fine-tuning from the Maine Principals’ Association’s Classification Committee during a nearly four-hour meeting Wednesday.

The proposal, which has been under consideration for more than a year, has been prompted in great part by declining student enrollments and the southward migration of the state’s population.

Those two factors have combined in recent years to swell the number of smaller schools in northern and eastern Maine while concentrating most of a dwindling number of large schools in the southern counties.

Seventy percent of the MPA’s 152 member high schools now have an enrollment of fewer than 500 students.

Panel members and committee liaison and MPA assistant executive director Gerry Durgin indicated that the five-class plan generally has been greeted with a favorable response since its unveiling last fall, though some schools expressed concerns about their individual statuses under the proposal.

“We’re at the point where I think 152 schools know we need to do something,” Durgin said.

The proposal faces more committee work before being submitted for final approval at a full MPA membership vote this spring.

The major step taken by the panel during the latest meeting was to endorse reducing the numerical differentials between classes used to calculate Heal points in basketball from five points per class to two points with the goal of encouraging more crossover games between schools in different classes.

Heal points are determined by a two-step process. In the first step, the preliminary index for each team is determined by adding points accrued for each victory (currently 40 points for a Class A win, 35 for Class B, 30 for Class C and 25 for Class D) and dividing that total by the number of scheduled games.

A team’s tournament index — the number that ultimately represents a team’s ranking — then is determined by adding the preliminary indexes of the opponent in all victories achieved by the team, dividing that total by the number of games on the regular-season schedule and multiplying that number by 10.

Under the proposal supported Wednesday, victories over teams in Class 1A — what the state’s new single-division, largest-school class is likely to be called if the plan gains final approval from the full MPA membership — would be worth 40 points, compared with 38 for Class 2A wins, 36 for Class 3A, 34 for Class 4A and 32 for Class 5A, the smallest-school division.

The endorsement of a two-point differential was seen as a compromise between the current five-point differential and calls by some conferences in the state to eliminate the differential altogether despite evidence that the differential doesn’t make a substantial difference whether it’s five, two or zero points.

Durgin offered as examples the final 2012-13 Eastern A and B boys basketball standings, in which teams finished in their identical positions save for a single one-position swap at the top of the Class B ranks no matter which of the three point-differential options was applied.

“We’ve had that type of evidence for the last six or seven years and it’s been discussed in other sports, so maybe this is just a tool to ease people’s minds about this,” said committee chairman Bunky Dow, activities director at Mount Desert Island High School of Bar Harbor. “But if it comes back that they want to keep it the same we can re-look at that before the final votes are taken.”

Much of the discussion was driven by the plight of Bangor, Edward Little of Auburn, Lewiston and Oxford Hills of South Paris high schools, the lone 1A programs that are members of the Kennebec Valley Athletic Conference rather than the Southern Maine Activities Association.

With no certainty that the KVAC 1A schools would be able to fill out their regular-season schedules with crossover games against SMAA A1 programs, Erskine Academy of South China athletic administrator Doran Stout expressed concern on the KVAC’s behalf that his league’s A1 schools might be at a competitive disadvantage in their efforts to earn high postseason seedings.

“Should the SMAA not choose to cross over and schedule games with the remaining Class 1A teams,” he said in articulating the KVAC’s recommendation to eliminate the Heal point differential, “those schools — Bangor, Edward Little, Lewiston and Oxford Hills — would have an unequal opportunity of earning Heal points for the tournament.”

Even if the SMAA chose to allow the four KVAC 1A schools to play its teams in crossover games, Stout said Bangor’s travel bill would be significant. with the closest A1 road trips for the Rams at Lewiston (108 miles one way), Edward Little (109) and Oxford Hills (134).

“And if the SMAA agreed to crossover games then Bangor would be making trips to the Portland area 140 or 150 miles away to get games,” he added.

Eliminating or reducing the Heal point differential would make it more attractive for Bangor to play some KVAC member schools pegged for Class 2A — such as neighboring Brewer and Hampden Academy, whom the Rams now play in Class A competition — to fill out the regular-season schedule.

The panel also slightly modified the proposed five-class enrollment cutoff numbers and advanced a four-class basketball format essentially the same as the model now in use to be implemented for the next two years in the event the five-class proposal doesn’t gain final approval.

The updated five-class enrollment cutoffs have 1A schools with 825-plus students, 545-814 for Class 2A, 325-544 for 3A, 121-324 for 4A and 0-120 for 5A. Enrollments being used for the next two-year cycle are those for each school as of April 1, 2014.

The committee also completed its biennial revision of enrollment cutoffs for other MPA-sanctioned sports during Wednesday’s meeting, and its recommendations for all sports — including basketball — for the next two-year cycle will be emailed to member schools for their consideration and then posted on the MPA’s website, www.mpa.cc, by early next week.

Among the recommended enrollment cutoff changes are reductions from 725-plus to 665-plus for Class A baseball, softball, cheering, boys and girls soccer, and indoor and outdoor soccer, which if approved would shift Camden Hills of Rockport, with an enrollment of 669, from Class B to Class A in those sports.

The Classification Committee is scheduled to meet again Feb. 24 to consider any appeals by individual schools or other feedback to the proposals, including the five-class basketball plan.

Dow said a second meeting may be needed for the panel to complete its work before it sends along its full classification report to the MPA’s Interscholastic Management Committee before that group’s March 12 meeting.

The five-class proposal and rest of the committee’s report ultimately will be subject to final approval by the MPA’s general membership during its annual spring conference, now scheduled for April 30-May 1.