Code:
   GateID_word.lowbyte[(T*2+1)+1] = SDC_buffer[250]   ' indexed highbyte +1                  ' copy temp varables to next index  
             GateID_word.lowbyte[(T*2)  +1] = SDC_buffer[251]   ' indexed lowbyte  +1


should be

Code:
   GateID_word.lowbyte[(T*2+1)+2] = SDC_buffer[250]   ' indexed highbyte +1                  ' copy temp varables to next index  
             GateID_word.lowbyte[(T*2)  +2] = SDC_buffer[251]   ' indexed lowbyte  +1