I do not believe I have access to the MS file you used for testing. If the Epson file is freely available can you post a link please? I would like to test with same file that you have also used.
I do understand the reports of the other systems - but - as a (very) old hand in the business you will, I hope, understand that a true test would require you to uninstall avast on your system and try McAfee and uninstall whatever on your wife's work computer and install avast. Comparing these systems - while not unreasonable - is not a truly reliable diagnostic and I certainly understand the limits that you might be willing to go to.
I think that you can appreciate too that, were this a more general issue affecting other avast users, this forum would be lit up like the proverbial Christmas tree.