Need SQL Actions - Plan Calendar Year different from Renewal

My client offers 1yr, 2yr and 10yr subscriptions.

ALL SUBSCRIPTIONS need to run from November 1 thru October 31. ALL Subscriptions need to end on October 31st REGARDLESS of what date they are purchased...with the conditions below:

If the Renewal Subscription is purchased AFTER November 1st (Current year) AND BEFORE May 31st (following year), then it is valid only thru October 31st (following year)

If the Renewal Subscription is purchased AFTER June 1st (Current year) AND BEFORE October 31st (Current year), then it is valid thru October 31st of the FOLLOWING YEAR. --- This encourages membership renewal in the months preceding the October 31st EXPIRATION of all plans.

How do I use SQL Actions to modify the Expire Dates properly when people sign up? I am guessing it would be an "If-Then-Else" ... but how?

Thanks in advance to whomever can assist!

I do not suggest modifying expiration dates. It's truthfully asking for trouble. Especially if using auto recurring of any kind with any gateway as the gateway would never know of the change. Single payments it is less of a danger, but it will still break calculations. The best I can suggest is to use the by calendar year durations and change the start month-year combo as needed then adjust the bonus time to 1 month.

Thanks for your prompt response. I appreciate your candor.

This client does not do recurring billing. I have been having to go into the MySQL database manually every so often and change the expire dates myself. It's just very confusing for the members to make a purchase that should take them thru Oct 31st ... see it extend it beyond that at the time they purchase ... then see it mysteriously retreat back to Oct 31st when I make my adjustments.

I would understand if you didn't want to publish the type of modification that I am asking for help with because of the harm it could do in other circumstances. If you could perhaps private message me with some suggestions and/or pointers, I would greatly appreciate it.

It has bugged my client since the first day we implemented this that I couldn't match the scheme dictated in their By Laws, and I've strung them along for several years ... now the heat is getting hot and I've got to make this happen.

Thanks, in advance, for whatever assistance you can give.