I simulate IP1dB and IIP3 for an amplifier with PSS+PAC, matched to 50ohm. The result shows that the IIP3 is not 10dB higher than IP1dB. Let's say IP1dB=-13dBm, but IIP3 is only -8dBm. I found that the IP1dB result is not the same if I took from PSS voltage gain or PAC voltage gain. One is -13dBm and the other is -18dBm. Which one is correct? Anybody met this problem before and know the reason?