Sanjay,
In that case, if the PABX is quoted to have BHCA of 32,000, it should not slow down if there is a high traffic of 4600 BHCA. It should function like a 32,000 instead of as mentioned by the supplier, the slow down is cause by the 2500 ACD BHCA, whereby my PABX have the BHCA of 32,000. Right?