We have the donation plugin, and it works great on our registration page, however, if an administrator wants to add a donation, it only lets them add multiples of $10. The client side allows for the amount to be edited to any dollar amount. In admin, if we need to manually add an invoice and payment for a donation, it does not allow for the dollar amount to be changed. Am I missing something or is there a fix for this?
Unfortunately there is not ability to change it form admin interface. You can use 'Login as customer' action and create invoice for necessary amount as user. Then add payment from admin interface.
This solution doesn't work very well for us, as our registration process is what allows for a donation. We do not have a separate signup process for people who just want to do a donation. Is there a plan to add this functionality in a future release? It seems like a basic function that should be included in admin if the end user is allowed to specify any amount.
I see you already submitted feature request to our bugtracker. We will implement such ability in one of upcoming versions.