That sounds inline with what I remember ours at. I believe we have a ~11 GB database last I checked and our nightly maintenance is usually under 4 min.
Hi Mark, I do recall the process being "fast". however, i noticed that you did not list update database statistics in your list of what's included in your maintenance plan. SOLIDWORKS recommends setting that up, you can refer to SolidWorks KB article S-067319 for details.