If it is not giving smoke then i will suggest to keep using it and also check for PCV valve for correct function....
Open oil always become less it... try to buy oil from authentic shops or from flagship store from daraz...
If done properly repaired engine is 100% perfect as new engine....
Oil repaired you are trying to say ring piston work or valve seal work? Or complete overhaul? And again properly overhauled engine is as good as new....
Mechanics will always suggest the biggest possible work as they will earn more
...
Once there was the problem with rocker arm of my engine, and one Mechanic told that engine dead ho gya hy...🤣🤣🤣
Summarizing my points,
First switch from these oils to authentic oils... and also test PCV valve...