ePMP Throughput drops when traffic loads

We have installed an ePMP point to point link using epmp force 110(achieved a throughput of 200mbps), all is working well but as soon as the traffics loads the throughput reduces to 100mbps and the latencies increases from 3ms to 55ms. We have tried doing spectrum analysis and changing frequencies but this does not help, the link comes up with high throughput then drops when traffic kicks in.