The latest new and updated apps with viruses according to Virus Total, why?

A typical end user is using their antivirus on their computer to automatically monitor all files as they should be. Generally this means Windows Defender, Symantec's Norton Antivirus, Mcafee, AntiVir, AVG, or similar. You'll note that none of them have these issues with false positives on any of the files you've mentioned. VirusTotal is not meant to be used as your primary scanner. It's meant to be a double-check on it. And it's meant to be used by advanced users that understand what false positives are. Typical end-users have never even heard of VirusTotal. It's also meant to be used by publishers to scan software about to be released to ensure that none of the major legitimate engines have a false positive. We don't bother reporting false positives to scanners like Bkav because they have false positives on every single file we test, so they're basically useless. It would be a full time job to try to report all their issues to them. They seem to ignore false positive reports in English anyway (they're a Vietnamese company).

The reason that sometimes a file will show a false positive by an antivirus and then the next day show as clean is because the antivirus companies update their definitions daily. So, they might screw up on a given file and then have to fix their issue the next day. Or their (generally horrible) heuristic portion of their scanner may flag a file as a generic malware possibility one day and they get enough user reports and complaints that they manually whitelist the file in their definitions update 2 days later. In short, Windows antivirus is highly imperfect when it comes to "possible" threats, so you'll get all kinds of generic "packed" or "heuristic" alerts on one or two antivirus engines on VirusTotal all the time.

The bottom line is that anytime you get a few alerts on a file but 30+ engines (including *all* the major legitimate ones) showing as clean, you absolutely know it is a false positive. An actual infected file or installer will look like that link I showed you above with line after line of red infected alerts with them often showing the same kind of infection on each.

It's also important to keep in mind that VirusTotal doesn't even match the real version of a given antivirus. VirusTotal will often have a file flagged on its web version when the standard installed commercial version of the engine will correctly show it as clean. From their FAQ:

VirusTotal antivirus solutions sometimes are not exactly the same as the public commercial versions. Very often, antivirus companies parametrize their engines specifically for VirusTotal (stronger heuristics, cloud interaction, inclusion of beta signatures, etc.). Therefore, sometimes the antivirus solution in VirusTotal will not behave exactly the same as the equivalent public commercial version of the given product.