The OmaticCloud format for PostOmatic does support the use of <ask> queries! There was an issue that we recently fixed in the latest version 126.96.36.199. You can find more information and a link to the download here: https://omaticsoftware.freshdesk.com/support/discussions/topics/28000008424
Hope that helps!
We recently found out while testing the OmaticCloud that we will no longer be able to use an query with an ask function in it when we run PostOmatic. We have been using PostOmatic for several years and have always used an ask query, whether we had it ask for the specific batch IDs that we were wanting to post or asking for a date or range of dates that we wanted to post. It would be great if we could continue to use this functionality instead of having to create/update a query each time we are wanting to post to include the specific group of records that we are working with.