Simple math. As example, Def.

Group:
25-30 lvl up costs 80 points. 80 * 3000 = 240 000. Its 12 * 4 = 48 stats for all ninjas.
30+ lvl up costs 100 points. 100 * 3000 = 300 000. Its 12 * 4 = 48 stats for all ninjas.

Eqv Str:
54->55 lvl up costs 51500. 51500 * 4 = 206 000. Its 7*4 = 28 stats for all ninjas.
60+ lvl up costs 106100. 106100 * 4 = 424 400. Its 8*4 = 32 stats for all ninjas.

Summ: forget about eqv, donate in group.