TPs is not matching VUs

Hi,

I'm trying to setup my LoadUI Test with exactly 25 transactions per second. So i setup my VUs to 25/s with 1 sec wait time and i'm using Fixed scenario. When i run the Load, the TPs is around 30-40. It's jumping between 30 TPs to around 60 TPs initially then overtime its decreased to 14-15 TPs.  Is there some other configuration which i need in order to achieve 25 transactions per second?