The time when you most want an AV running is when installing software.
Contrary to what many say there is no need whatsoever to disable your AV to install their software and when anyone tells me that their software is history.
If what they are doing requires your security application needs to be disabled I have to wonder what they are doing/hiding. If they aren't doing anything underhand or suspicious, that an AV may interpret as an attack.malicious, why would they need to even suggest disabling.