Ah, thanks!
Hmm.
Looks like much of what was different in Shirou's experiences was due, directly or indirectly, to the interference of his possible future self.
I suspect the big turnaround probably happened at the big fight vs. Berserker. It says he didn't necessarily have a sexual relationship with Saber and Rin, and that he "failed to free Saber," so that probably means Saber lost that fight. The fact that Archer!Shirou hadn't learned projection until much later than that fight reduces their chance of victory to nearly nothing.
...Is it just me, or does anyone else get the feeling that the friend who betrayed EMIYA was Matou Shinji? Starting shit, getting in trouble, being saved by Shirou, then blaming the trouble on his rescuer... that sounds suspiciously like Shinji's MO.