VO2 Max and race pace disparity

Hi, 

My garmin says my VO2 max is 41 (good) and that corresponds to a 5k race pace of 25mins. However, when I check my most recent races against the VO2 max chart my VO2 max should be around 30 (poor). My 5k pb is 30 mins, 10k = 1hr 2 mins, and 1/2 mara = 2hr 19 mins.

Is the VO2 max wrong or do you think it is something wrong with how I’m running maybe? I cannot go faster than that 5k pb, last time I tried my HR went over 200 and I nearly passed out!!!! 

Please help by offering suggestions. 

Many thanks,

Vic