There is one thing that is true, not all returns take the same time to process at IRS.
It may be that there are some topics on returns that IRS is looking at more carefully and your return might have it, or your return may have been received in a huge group of returns to be processed and IRS is struggling to catch up. Since the return has been accepted, then just take advantage of using the tools on irs.gov to check on your refund status.
It is not uncommon to take 4 weeks or more to process return refund checks in the beginning of tax season.
