The Global 30 Day Pass covers the US, so you won't be billed the $16/day US Easy Roam pay per use on top of it. The $125 is the one time charge for the pass itself, not a separate Easy Roam fee.
The US Easy Roam showing on your account is the standing pay per use roaming entitlement that has to sit on the line for the device to roam at all. It only bills at the daily rate when no pass is running, so once your 30 days are used up or the pass expires, roaming goes back to pay per use https://www.koodomobile.com/en/services/easyroam
Before you fly I would check Self Serve > Mobile Services > Add-ons and confirm the Global 30 Day Pass is listed there. there's a known glitch where the confirmation only mentions extra data and the pass never provisions.