You mention having to activate APL64 in your Q&A document. I have no problems having to purchase and activate a development copy of APL64 once (provided the cost is "reasonable" [TBD]). But I would object to having to repurchase and reactivate it on a regular basis if I have no pressing reason to upgrade the version I've already got. I can see large corporations needing to keep up-to-date and paying for new versions as they become available, but small developers often don't have those kinds of resources and don't always need to stay up-to-date with the very latest interpreter.
Are you planning to require regular purchase renewals even without upgrades?