Hi,
Before applying notes, have you checked ecc job log what it saying and where its taking more time.
Even you need to consider about ECC and bw servers busy schedule.
how many app servers you have?
during your load time have seen tx - SM58, due to the server busy your idocs will late to reach bw server.
Try to run your data extraction where ecc and bw have less burdern on them.
if you have any enhancement code, with help of abap expert, try to tune that code.
Thanks