Packet sending rate

I am trying to get the watch to send out a set number of packets per second but am having some difficulties. I have tried changing to software on the watch but have not managed to sort it out. We have set the sampling rate to 100hz in the vti_as.c. Have also changed the simplicti_get_ed_data_callback to send only every 10th packet. On the windows side we are using c# function to pull the data from the usb reciever. Currently though we are getting a range of between 6 and 40 samples per second. Any help would be great!