Hi, i want to go to Tibet for group tour. can i get "extreme unguent" visa in 1 day?

i am short on holidays and need to apply n Kathmandu in 1 or at max 2 days to avail a group tour in Lhasa. the Embassy website shows 3 categories by paying different fees. wanted to know the time taken under each category. whether "extreme" urgent" is it in 1 day or 2 days etc?