Thanks both again.

County and Title is having different version of explanation. County said they don't have a rule for which installment covers which period.
Anyway, this is not a lot of money so not worth a mess of trouble.I will pay for the 4th installment.
However, really feel pissed off with the way how title was handling it.
They messed up the thing from begining and owed me an explanation on all this.
If possible, I want to file a complaint on this.