Qustion regarding alimony payments.

Generally, the court order controls (there are some case that indicate that parties may orally modify agreements, even those in writing, but generally oral agreements do not modify court orders, and it looks like you, at least, had no intention to actually modify the sum payable, only the installments of that payment. People make this mistake all the time (that is why 4 payments a month does not equal 52 payments a year). I suggest that you write a letter, explain that you owe $600 per month, and that you will make $150 per week payments each week until $600 has been paid, and then no payments until the next month, and see how she responds.  If there is an actual dispute, you will at least know what she is asserting you agreed to, and can decide whether it is worth it for either of you to file a motion.  Of course, you have control, in that you simply have to not make the additional payments, and you will know soon whether she thinks it worth while to push the point.