Indoors and outdoors are two different things. Most folk can push higher outdoors due primarily to air cooling. I’m the opposite I push harder indoors when I don’t have to worry about traffic and falling off. So my numbers with my be pro s are slightly higher indoors as compared to out.
You could run both the Taxc and Be ProS in parallel indoors. Say Taxc on TR and the Be Pro S on your head unit. Then see what the difference is (some is probably reasonable) and you won’t really know what is too high or too low.
I’d just do all your training indoors and out with the Be Pro S, it doesn’t matter if its wrong as long as its consistent and you can’t exactly take the Taxc outdoors on a ride 
