That sucks!
Of course you want your system to work flawlessly, but I bet you were hoping it was acting up when the tech came.....
It is really difficult to diagnose a trouble like yours, especially when it is working fine when the tech is there....
I still think it could be a sw44 issue, as a failure of one input (ie 82 -13V) could throw off the signal.
These sw44's are rather finicky when it comes to the length of copper connecting to the sw44 (they have to be a bit longer)
I had them flush with the connector, but it wasn't long enough, so I had to extend them about 1/4" so they were making contact when screwed on
This could be caused by a failing LNB, switch, connectors, etc....