I'm not tpd223, but I'll bite.

The 124 gr. is giving ideal penetration, 115s tend to give a little less, so underpenetration could be an issue with them.

If the 124+P is penetrating deep enough, going heavier (147) will give more penetration that likely is not needed. Because the bullet is heavier, it will be traveling slower and closer to it's expansion threshold (the velocity at which a bullet will begin to expand). As bullets get closer to their expansing threshold, their performance (as in reliable expansion) tends to become spotty, especially from shorter barrels. Also the heavier bullet will be lower energy (velocity is a better builder of muzzle energy than bullet weight is). I'd rather use a bullet that is too heavy than one that is too light, but if the 124s are working well, then the extra weight of the 147 is unneeded, and a robber of optimal performance, unless it is more shootable, more accurate, or hits POA.