crawl interval time takes more than scheduled

Dear all

I have SharePoint server 2010 with FAST Search server,

I Schedule Full crawl and Incremental crawl, Full crawl will run every night 12.00 am and incremental crawl will run interval of every 1 minute , each incremental crawl will take about 1 minute 40 seconds, After done one incremental crawl , the next incremental doesn't in the interval of one minute. it start in the interval of 3 minute please find the below screen shots

First image is Crawl settings and crawl Schedule ( http://i46.tinypic.com/23p5oi.png )

Second image is Incremental Crawl Schedule  ( http://i47.tinypic.com/2ef7pee.png )

Third image is full crawl Schedule

Fourth image is Crawl Log -Crawl History

Please advise us why its taking 3 minute instead of 1 minute...aslo pls advice us how to fix this

Thanks in Advance

Sathish Kasinathan

Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.