I believe the minimum points for conversion is 5000 at one time and it is not based on months. If you accumulate 5000 points twice in a month you can withdraw two times in a month. Am I right ?
If per day you can reach 15,000 points = $150 and you active to contribute in OC everyday in a month (30 days) so you will get max $150 x 30 = $4500. Can you imagine it?