Each bonus granted is cumulative in effect. For example in my last attack against Syke (whiny chum I might add ), he had the following bonuses:

57 Reapers of Death (146 base power, 100% defensive bonus)

Two implants with 19% defense bonus

84% shield

15% racial

The bonuses are not added, then applied to the power (this is not 237%). Instead, each is cumulative to the total. The calculation currently works like:

57 (number of units) * 146 (power of the unit) * 1.19 (implant) * 1.19 (implant #2) * 1.84 (shielding) * 2 (unit bonus) * 1.15 (racial)

This equals 49873, which is the total power he provided during this skirmish.

If this calculation is what is intended, it heavily favors the higher level player. In later stages of the game, it will provide a huge power disparity between players that will abuse the calculation by sending few units (multiplied multiple times with bonuses) and wiping out much larger armies.

And just to put it to scale, 237% bonus with those units would be 28045 power. You can see the power gap between the two applications of the bonuses.