How to classify blisters?

Scenario: Res was found to have o/a's on lateral aspect of LE's, where the legs come in (near) constant contact with pillows used to float heels. There was also an intact, fluid filled blister. O/a's have red wound bed, with scant amt serous drainage. Peri wound pink and blanches to touch. Areas along bone of leg. Res requires asst to turn et doesn't move much under own power. Nutrition an issue and gets tube feeding. On low-air loss mattress. Stage IV on sacrum (admitted with that one) with wound vac in place.

Question: Was I wrong to stage the o/a's as a II? I staged them, did the paperwork and fax'd the MD with pertinent info to order tx. Last night, I found the fax that I had sent with a message written under my assessment by another nurse that stated that area's are from shear and not pressure. ??!! What's the difference? (I know the difference between how the 2 are created, but is there a distinction according to how state sees it?)Isn't a o/a due to shear still a stageable area?

WARNING, RANT AHEAD: And furthermore, I'm really irritated that this nurse completely undermined my assessment on the very same page that I had fax'd the MD on without discussing it with me first. Now, I feel like anytime I call or fax the MD with anything, they may remember my name and question my assessments. (They likely won't remember, I know, but STILL). I feel it was totally inappropriate. If I was wrong, fine, but even in report this nursing had already begun to deny they were pressure areas without even looking at them. I try, ever so hard to not allow myself to get caught up in shift wars, but this certainly feels like that's what it is. I'm the new-ish night nurse and the day nurse is shutting down everything I try to accomplish to care for my residents. Sorry for the novel, but I care very much for my residents, and it just makes me mad that not only do I get shut down, I don't even get an explaination. TEACH ME!!!!!!!!! I'll listen!!!! I plan to approach this nurse as diplomatically as possible, but would like to know if I should not have classified the o/a's as pressure, please let me know why/why not. At least I'll know what to discuss and maybe get some ideas of what to look for to stage or not to stage an o/a. Thank you in advance for any help.