It is technically not a glitch because the reason it still takes your sP is because it is adding time to the three slots that you can have. So instead of 1 month, it lasts for 2 months. But I will look into either blocking the purchase of more time or if that is not feasible, at least put up a disclaimer to let people know that 3 is the limit.

The OLLs should now be the same as a regular slot just paid a different way. If the OLL took a long time to expire that may be the reason for the weird number.

Are you still having trouble with this?