Power Zones

Hi all,
I’m new to Zwift and am somewhat confused about the percentage of power zones. My set up is a dumb trainer using vector 3 power pedals. My FTP test was 251 on Zwift. After a group ride, the data from Zwift to Garmin Connect showed the following for my power zone ranges.

FTP 251
Data uploaded from Zwift to Garmin Connect

Zone Range Time
Z7 300+ 1.19
Z6 240-299 4.23
Z5 210-239 24.11
Z4 180-209 21.50
Z3 150-179 8.43
Z2 110-149 6.52
Z1 50-109 2.52

However, I have noticed that percentage of zones taken from Dr Andrew Coggan – trainingpeaks.com shows different zone ranges.

Z7 Maximum
Z6 121%+ 303
Z5 106-120% 266-301
Z4 91-105% 228-263
Z3 76-90% 190-225
Z2 56-75% 140-188
Z1 -55% 138

My question is, which one is correct? According to the zones from trainpeaks, Z1 is 138 watts or under. However, Zwift to Garmin shows that the 138 watts would put me in Z2.

Or, if I was to keep to 200 watts for a certain duration, would that put me in Z4 (Zwift/Garmin connect) or Z3 (trainingpeaks)?

Like I said, I am completely new to this and am trying to get my head around the numbers etc. Any help or advice would be greatly apprectaied.