Not so fast... If you HOLD an IR(H) - you can get the IR(A) in 10 hours.
If you don't - you'll need to do a full course at an ATO which for SEIR will be 35sim/15sep=50 hours. It's unlikely that they'll credit your FNPT2 time as it's (a) configured as a helicopter, and (b) not their sim on their course. You may have more luck crediting if you do a CBIR (which is only 40 hours anyway.)