I wouldn't. I think they complement each other, and the FA pathology sections are usually around 30 pages so it's not like you're eliminating a huge time drain. The one example that stood out to me was I missed an amenorrhea question on my schools reproductive path exam and the answer was Kallman syndrome which was covered in FA (which I had only glossed over) and missed by Pathoma. If Pathoma covers the unit entirely, it should make FA a quick read anyway giving you the chance to fill in the details from Pathoma and reinforce what you've already covered.