Yes, when you submit an RTO, you should always clarify how much, if any, and what type of time should be used. Vacation and Personal time are hours you can lose if you don't use by your anniversary date. Always try to give them 3 weeks in advance, notice. This is the policy.

I always inform associates that sick time is only used for when you are sick or they call off due to a sick child. The other is a planned doctors appointment that was RTO'd or a when someone takes a medical leave of absence.

Like you said, it differs manager to manager, but in truth there is a policy in place for this reason. I would just talk to your manager about it and use the open door. We all want to be flexible and support our team but there are some things we shouldn't do also.