EVCS auto charge from excess solar - how is the solar calculated?

Hi Folks,

Apologies in advance if I missed this in the manuals, online FAQs and training videos.

I saw a hint of the answer in another thread but would like to confirm if I may.

My setup is:
ESS/Multiplus2/cerbo gx/ - Victron VM grid meter - Grid tied solar on AC-IN

In the VRM portal for my install, without a way to directly measure, Solar production is not displayed, AC consumption is shown as 0 watts with any excess exported to grid.

However in another thread on here there was a hint that the actual calculation used to trigger the EVCS Auto charge doesn’t use this VRM Solar figure and instead uses the battery charge rate : or to put it another way “Multiplus 2 battery charging at 3000w means there is at least 3000w of Solar available”.

Is this correct? I would really like to purchase this device and utilise it for Auto charging.

Thank you for your time.