Issue with maint. plan no range continuity..

Hi,

I have a issue regarding maintenance plan number range. I shocked after seeing that number range is going to reversal.Here I started to create a maintenance plan with 10000371 and next was 10000372. After that when user create new maintenance plan that is started from 10000364 10000365 so on while these number has skipped.

What are the reason behind this I am unable to catch. Can internal number range go back side or reverse.

Thanks

Regards

Gaurav Solanki