All of you are following/unfollowing/liking 1000s per day and you're worried about API calls made to delete comments or posts? Don't be
I'm using both features and I never had an issue.
I deleted more than 400 posts last time in just couple of hours and account is OK.
I'm running delete comments tool constantly on my accounts in order to delete comments such as "fake, survey, spam"... and don't have issues at all.
I would say there's no risk from using this tool. Make sure your other tools have right settings.