Doubt it has anything to do with money and everything to do with not wanting to look like they are going "big time".
Obviously holding it at the number 1 seat seed makes more sense as they chose a site with limited capacity but best guess is they need time to prepare in advance and had to have a venue determined before the latest date the number 1 seed might get decided.
Ticket sales don't drive the primary revenue streams of most events. It's sponsorships and other revenue sources.