If the 2 up/2 downs are a pain to do and include a lot of bad payers you could consider dropping them to give you more time for the rest and to get better priced better work. Or you could put the price of those 2 up/ 2 down jobs up to make them more attractive, some might refuse which frees you up a bit and anyone who keeps you on at the better price means the job might be a bit more attractive.
Or if you want to keep them why not put your customers , or some of them, maybe those 2 up/2 down jobs, onto a 5 or 6 week rota.