So this latest episode of Yahari Ore no Seishun (ep. 11) just basically blitzed through the majority of volume 10. Like 80% of the LN lol. Given the context of the story from the volume though, it kind of makes sense. And they did highlight the more or less important parts of the volume (hi2u infirmary scene).
Edit: Looks like Ep.12 and 13 are going to be anime original content. Volume 11 is supposed to cater around a valentines event that the student council is setting up, but episode 12 is about making V-day chocolates and blahblah. So there's that I suppose. 10.5 will come in OVA form I guess?