AT&T International Day Pass on 1st eSIM, plus a separate Local-Country Service on 2nd eSIM

I need clarification on Charges when using an AT&T International Day Pass on my iPhone 14's 1st eSIM, plus a separate Local-Country Service on its 2nd eSIM.

I'll have the AT&T Int'l Day Pass on my 1st eSIM line when I travel to Italy this coming month.

I plan to use the 2nd eSIM line to get a local-calling/local-data service (perhaps Vodafone or O2).

It's my understanding that I'll be charged the Int'l Day Pass $10/day charge for the first 10 days of actual use of my 1st eSIM line, but that I will *not* be charged by AT&T for use of the 2nd eSIM line for a local-country provider service.  CORRECT?

I ask because my cousin tried to do this on a recent trip of her own, but reports that she ended up getting charged the $10 on her second line as well, which was being used (as I plan to do) for a local service provider, and NOT as a second Day Pass line.