99512 would be an inapproiate code for sleep apenea / tap appliance as the code is used for Home Health visit for hemodialysis. They may have transposed the numbers and it should be 99215 for an exam, however, even that would be considered over-coding as it would be difficult to meet the criteria for a level 5 exam off sleep apenea. A more appropriate exam code would be 99213.
The other codes being used appear to be appropriate E0486 is an oral device that includes custom fabrication along with the fitting and adjustment. If this is not a custom fabrication you should use E0485 instead.
92520 is for laryngeal function studies which would be appropriate for sleep apenea studies.
Please check the ADCA data base there are specific codes for Tap appliance and appropriate codes depending on the scenario.