Call Forward Delay

Hi, I currently have a PBXIAF in softlayer datacenter and all works great. The only thing i have a problem with and was wondering if there is any type of tweaks i can do is:

Lets say someone calls our main number and the front desk girl picksup and we are not in the office, she then can transfer it to our cell phone we are using two diffrent very good SIP Providers Vitelity and VOIP INNOVATION we get the call to our cell phone and all is good, however there is a delay in the conversation. by like a second so you have to talk slower

I know i’m not the only person with this problem, does any one have any suggestions ?