@Surya ********
I wouldn't count on an actual 15 days. They've NEVER given that much notice for any immigration change. As an example, on June 10th a new immigration policy was published in the royal gazette, and it was effective May 28th. This is much more typical of how things happen.
Is it really worth risking to save $40? The visa is valid for 90 days, best to just apply for it if you already know you need the 60 days on arrival.