Really, I think it depends on how much you are absorbing. The standard utrogestan dose is either 100mg continuously or 200mg for days 15-26 of the cycle sequentially. If you're on 100mg, I'm assuming you take it continuously?
Whether to increase really should depend on your estrogen levels, not on how much you are applying to your skin. Some women on 4 pumps of gel might have just 250pmol of estradiol. Others might have 650pmol. Increasing based on dose alone makes no sense. Much better to do bloods and see what your levels are and then decide. Or go by symptoms - if you get breakthrough bleeding for eg. (Bear in mind it is normal to bleed unpredictably up to 3 months after an increase of estrogen. This doesn't mean anything as it's just your body adjusting. But if you continue to bleed randomly after that, you will need more P.)
But at the moment I would focus on getting you estrogen levels up, checking bloods to be sure they are high enough and in the therapeutic range - and then focus on the progesterone and fitting that to the estrogen dose.