There is no real controversy on this - the licensed dose specified by the manufacturers is for the same dose to be used vaginally as orally. This is correct.
That being said, there have been trials with SMALL numbers of women, showing that for low to medium doses of oestrogen, HALF the amount of progesterone can be used to give the same protection to the womb compared with oral delivery. Note the oestrogen doses - low to medium. This has not been tested on high doses if I recall correctly - in the same way that all doses of progersterone are dose dependent ie more prog needed for higher doses of oestrogen, yet most docs just prescribe the licensed dose ie 200 mg for cyclical and 100 mg for conti use.
The danger is therefore extrapolating this finding to cover ALL women and ALL doses of oestrogen including the higher doses of oestrogen that are often prescribed today especially by some private clinics. The BMS gives the correct view - has researched the literature and come up with recommendations based on the evidence available.
As sheila says though too, therefore, as you are on a medium dose of oestrogen, you may well be OK but my recommendation would be to take it as your doctor suggests - but 12 days per 28 day cycle unless there is a medical reason for you to take it for 14 days, as it is 12 days that is the licensed dose.
Start off with this and see how you get on re bleeding etc - if you end up having almost no bleed then perhpas venture into 100 mg vaginally.
By the way I always get urinary frequency when on the utro phase of my cycle - especially at night when I have to get up, whereas I don't normally provide I don't drink too much (of anything) in the evening.
Hope this helps
Hurdity x