The two times I have had to pay on an overstay once in 2005 and once in 2007 first 2 months over and second 3 months which according to the tarriff chart should have been the same $40 US.
I paid 500 pesos (Las Americas) the first time and $20US (Punta Cana) the second time. I know the money went straight into his pocket as I saw him do it....lol and they did not stamp an exit on my passport both times which caused me a problem on the second occasion as they wanted to charge me for being 1 year over $100US.
Still good to see enterprising staff still exist in the Immigration and passport control ....lol
Skippy1