supporter price limits and period

How to change the limits of the supporter price?
In the supporter administration, is there any way to remove the 3 options (1 month/3 months/12 Months) and choose, like it is on Membership, only one period?

The limits of the supporter prices I've found where we can change, but still need to know how to change the period :wink:

To change the limit go to \wp-content\mu-plugins\supporter-framework.php

for 1 month period: Line 1278: for ( $counter = 1; $counter <= 999; $counter += 1) {
for 3 month period: Line 1307: for ( $counter = 1; $counter <= 999; $counter += 1) {
for 12 month period: Line 1336: for ( $counter = 1; $counter <= 999; $counter += 1) {