Originally Posted by
DaveSSS
Not a brilliant answer. The OP didn't ask anything to be explained.
The difference between those two angles is meaningless, since the STA determines what might be the best seatpost setback to buy and HTA has no significant effect on the fit. It has a 67mm trail and will handle accordingly. Anyone who thinks there should be a correlation between HTA and STA is mistaken.
HTA has a significant affect on handling. When I was considering this frame myself last year, it had by far the slackest HTA of any mainstream endurance road bike I could find. All the others were between 72.5 to 73.5 degrees from memory. I agree the relationship to STA is irrelevant. STA on this frame is pretty standard anyway. It's the slack HTA that stands out to me. That and massive tyre clearance.