> If an admin makes a post that he or she did not make as an HTML post but then later edits this post the option to use HTML is not there.

That is a "feature" in 7.1.   I got around it by issuing a back door SQL command (CP, Database Tools, SQL command):
Update ubbt_Posts set post_markup_type='both' where post_id=12345

Instead of 'both' you can specify 'html' or 'markup'.