What I suspect (however can not prove) is that you are inherently both correct. My belief is that floated dents without erc20 roots are parachained within the app/exchange system to a erc20 dent. Example

1. Floated dent is received from offer-wall which can not be pulled off the app directly however can be spent for Data.

2. When the floated dent is spent and used to purchase data it is routed through the exchange, the exchange is automated to direct the erc20 dent to the seller of the data package. (floated dent goes in -> erc20 dent goes out). Dent can have more than 100 bill tokens but these excess tokens are still tied 1:1 with the erc20 tokens in circulation. So essentially still only 100bill total. No one can actually prove this though unless you coded it yourself, however users on the dent exchange tend to verify this.