Ability to “complete” sponsor tasks

I’m talking about the actual tasks and not the reward progress. Right now, we can pay 25 tokens to advance to next reward level but sometimes at the end of the season we are short of just 20-30 points to the last reward and it feels such a waste of completed tasks. Why not introduce, say last 3 days of the season, the ability to pay tokens to complete tasks. For example, since advancing 1 level is 25 tokens, then set the price of a 120-point task at 20 tokens, and 40-point task at 5 tokens etc. This way, I can pay 5-10 tokens to get one last reward without having to pay 25T. There could also be a limit of 1 or 2 such actions to prevent exploitation like waiting til last 3 days and paying less tokens to complete several tasks all at once (compared to 25T for each reward).