If you have a consistent UOM for things, then your DBA’s policy is OK.
For example, if timespans are ALWAYS in minutes, etc.
If the UOM could change, then you should store it in another column, alongside the qty.
That said, I tend to side with you on this. Clarity trumps most things, including this. I’d rather see DurationMinutes than Duration and have to guess what the UOM is.