Well, from my experience (been mining with amps almost all my
EU life), i can tell that amps do not amplify individual claims, but rather the whole output. If let's say, your average return is 80% in tt. So, if you drop 300 bombs, unamped, your return would be aprox 300*0.8=240peds. Now, if you drop 300 bombs amped with oa-103, return would be (300+300*2)*0.8=720peds.
Same rule should apply to mixed amped/unamped runs. If let's say, you drop 200 bombs unamped and 100 amped with oa-103, return would aproximately be (200+100*3)*0.8=400peds.
Hope it clarifies things a bit.