Are additional losses incurred when using Amplify?
Assuming that the track is 32-bit float format (the default), then in normal circumstances no, there are no losses caused by the Amplify effect. Amplify just scales the waveform to a higher or lower level (with 32-bit float precision, which is extremely precise).
In a stupidly extreme case, such as amplifying by -80 dB (which would have to be done in 2 steps because the range of the Amplify effect is -50 to +50 dB), and then amplifying back up again, then yes there would be some loss of precision. (50 dB amplification is equivalent to over 300 times amplification. 80 dB is equivalent to 1000 times amplification.)