Question

If I upload documents to the skill in the Advanced Designer, will it decrease page counter in my subscription?

Answer

Yes, pages are counted both during the design time and runtime.

More details can be found in Help:

EU: How Pages Are Counted in ABBYY Vantage 

AU: How Pages Are Counted in ABBYY Vantage

US: How Pages Are Counted in ABBYY Vantage