Opponent hasn't landed properly on the floor yet; means you're too early. You'll need to time correctly or use some known pseudo FTs [check Pai pseudo FT thread or wait for my next vid] or FTs like 6H+K
Pai has some really good and safe pseudo FTs. 46H+K P PP P+K is a good one. 46H+K 9K 9K 66H+K is something I like to use since it gives you lots of good options
such as [BT] 4P which is +3 FA on block or [BT] 9K which is +3 FA on block. Hope It's not too detailed/complicated; else ask me again and I'll explain it easier to you
Just PP; it makes the enemy fall to the ground much quicker.
If you hit [BT] 4P on block, your next hit will need 3 frames less. So your 6P will be 8 frames, instead of 11 frames which means it will beat any strike/throw of your opponents (since fastest strike is 9 frames)