L1 phase center or average L1+L2 for Antenna Calibration? (CGO2/landstar8/igage)

See actual question at the end. Unnecessary background info:

I use CHCNav CGO2 for processing a static network (logging from cors sites & on-site bases). I use LandStar8 field software (android) for all my base/rover fieldwork. Vectors from CGO2 and Landstar8 go into Starnet for adjustment (and TS data, but not relevant here).

I use iGage iG8 receivers, per NGS Antcal data: L1 phase center vert offset=114.00mm, and L2=91.07mm.

I loaded the iG8 .atx antenna calibration file from ngs directly into CGO2. LandStar8 loads all the iGage antennas when you install the USA localization package.

CGO2 is using the average of L1+L2 phase center vertical offset (114+91)/2=102mm

LandStar8 is using just the L1 value=114mm.

I stumbled the internet a little and couldn't find a clear answer on which I should be using. I presume being consistent is ideal, but I still have two options in that case.

For phase center vertical offsets in gnss processing: Should I be using the L1 value or average of L1+L2?