Since nothing is collected up front or at closing and you don't keep a cushion, you don't have to disclose anything on the HUD-1.
Depending on your origination software, if it calculates the aggregate adjustment based on no cushion, you could try entering 1 month MI premium to see if the net effect (all escrow items less aggregate adj) is the same as not disclosing anything.
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ZOMP! is a registered trademark of MGIC. I've cut & pasted the basics of this MI plan below for those who are not familiar with it:
ZOMP = Zero-Option Monthly Premium Plan. The initial premium is not due until the month in which the borrower's first monthly mortgage payment is made (e.g. premiums are for January are billed in January).
MGIC sends you Premiums Due Statements around the 10th of each month.