Are you doing this because you have a) loaded additional historical data, or b) made corrections to historical data, or c) changed signature values on a specific activity and wish to recalculate moving forward? Those are the normal reasons to recalculate progression besides the option to reset under Account Settings.
I would choose the lower value since your TP will be validated (and updated) when you have your next breakthrough (BT) event. You can trigger that by selecting a BT workout and riding it in slope mode, or riding outdoors with BT efforts in mind.
XATA will warn you when your signature is getting stale, but it’s up to you to manually make BT’s happen. It won’t show up on the recommended list.
BT workouts can be located in the library by searching for “breakthrough”.
For tips on generating BT’s outdoors see article link below.
Xert recalcs your signature after very activity whether a breakthrough occurs or not. Numbers decay when there is lack of activities that generate breakthrough events.
Numbers can go up and down depending on what type of breakthrough event occurs.
Consider your fitness signature as a fluid set of gauges.
Decay rate is based on Account Settings, Profile, Signature Decay Method.
Optimal is the normal setting unless you expect a prolonged period where you won’t be generating breakthrough events to validate your signature in which case No Decay can be used.
Reference:
When to use the ‘Recalculate Progression’ feature on your Fitness Signature – Xert (baronbiosys.com)
Signature Decay Method – Xert (baronbiosys.com)
Breaking Through the Xert Way! – Xert (baronbiosys.com)
If you are new to Xert there are lots of newbie tips posted in this thread –
Beginner questions - Support - Xert Community Forum (xertonline.com)