This exact thing was happening to me. Same numbers too. I crushed my last ramp test and increased m FTP by 25W to 230. Needless to say the subsequent workouts were brutal! So I dropped it down to 210 and am going to go from there. I might try the 8 or 20min tests next go around.
I think FTP is important but you gotta be able to do the work and get quality work in.