How does power on TV get missed?
Are you referring to the user not pointing the remote at the TV, so it ends up not coming on? Now your flag has been set and they would have to hit power off to clear it, correct?

Using macros with long wait times on an IR only remote can be tricky. The client has to understand that by not buying the whole kit (even an RP1 can help) they have to put up with this possibility. And may have to press other buttons to get things "reset".
Or you give them TV on / off buttons if using a remote with a screen, jump to a please wait page then to source selection. By now they should be able to select what ever they want and have no issues with switching inputs.
Better than expecting them to "hold" the remote while all the codes are being spit out.