Correct, if you are going to process over $1,000 a month - go with your own. This normally covers a monthly minimum of $25.00 that some processors do require. With you processing $1,000 at 2.25%, that is $22.50 a month. You would still be respsonsible for $2.50 but as long as the discount rate totals more than $25.00 a month, you have nothing to worry about.
I suggest to most of my clients to keep paypal there as an option. So many people do use that to transfer money back & forth, it could not hurt & just helps to expand your business. But only using Paypal does not look professional in my opinion and others.