We do not recommend increasing by more than 2X the current supply cap.
As stated in the methodology, we assume that additional supply and borrow amounts will be distributed similarly to the current supply and borrowing activity. Therefore, we wish to limit the increase to 2X the current cap to accommodate any unexpected borrower and market behavior deviating from the above assumption.
In the methodology, we also discuss the 0.9 figure:
It was chosen as a conservative limit, not completely arbitrarily, as you suggest in your comment. The community can decide on a less conservative approach, which may lead to higher caps. However, we do not think that is necessary as even with the current model, we are not limiting cap increases across the board.