Originally Posted by
vsevolod4
The big question is parity at time of conversion. Lifetime US miles are more restricted than lifetime AA miles.
It is a bit more complicated than that. There is
currently parity in the AA and US systems for counting MM. Both use BIS miles only.
You are absolutely correct though that for years AA's MM counter included elite bonus miles, credit card miles, promotion bonus miles, AAdvantage shopping miles, etc, etc, everything. That changed in summer 2011 when AA moved to the BIS miles only.
So at this point, we have 2.5 years of 'BIS only' parity (and by the time merging occurs perhaps 3.5 years of parity). It could get quite complicated indeed to calculate an uplift amount only for US miles prior to summer 2011 while not uplifting US miles earned summer 2011 and later.
(If all US miles are uplifted, than AA miles from summer 2011 onward would have to uplifted as well to maintain parity)