Good and bad news

Good is that .7062 does scheduled full scan on reg. user rights on win 10 but bad is it hogs all hdd bandwith making comp unusable unless app was already running when CIS started scan.

This is reproduceable on a mechanical hard disk drive.
You may have already tried the following, but I just wanted to check if you tried lowering the priority the manual/scheduled scans?

This may help keep your PC usable while a scan is being performed, however it may take more time to complete.

used to that CIS isn’t doing scheduled scans so that’s not ticked.

I don’t believe it has to be a scheduled scan. Those options should apply for the scan “profile” itself when you initiate a manual full or quick scan. I would recommend applying a lower priority to them and see if it works.

If you think this is not the case that’s fair enough.

have been relying on scan on access so not doing any scans.

will keep that in mind