Is it so that roaming data that is used comes off of my allotment at an accelerated rate?
Yes. From Republic Wireless Plans 2.0: Republic Refund :
Can I still use roaming cellular data on the Republic Wireless Plans 2.0?
Yes. When you’re in a roaming area, it will come out of your overall cellular data amount. Keep in mind that roaming cellular data** is applied towards your cellular data amount at a faster pace (1 MB of roaming cellular data equals 18.3 MB of native cellular data)****.** With the new version of the app, we’ve added notifications to let you know when you’re in a roaming area and the ability to turn roaming cellular data completely off. Roaming cellular data is turned off by default in the app for Republic Wireless Plans 2.0.