Your target is 798 and this is what you've been getting:
T,T,T,T,H,H,T,T,T,T 3D0C0312 14 776
T,H,T,H,H,T,H,T,T,T 3D0C0316 14 780
H,T,T,T,T,T,H,H,T,T 3D0C0320 14 790
T,H,T,H,H,T,T,H,T,H 3D0C0313 14 776
T,H,T,H,T,H,H,T,T,T 3D0C0311 14 774
Basically, your results are pretty varied, but 776-780 range is pretty close to consistent. So this means that your timing on when you press "a" for pikatimer is really making you hit delays 776-780ish and not what you want - 798. So you can use the "Other Delay" box of pikatimer to enter in what you're hitting so that pikatimer can adjust the timing for you.
Thanks, Bakus. ^^