Here is the comparison of the Mitsubishi PA and NXP PA.
The main signal is at 887M GSM with 39dBm, the insertion loss is 8dB for freq <=885M.
Mitsubishi PA causes some spurs at 770M, but the spurs level are below -55dBm.
NXP PA causes spurs at the same freq, but the levels are about -47dBm.
Both with the same input.
The standard are below -36dBm, if added 8dB, i.e. -44dBm.
So I think that is the difference of the PAs, different PA cause different spur level.