So at around the 7:04 p.m. mark of the Miami-Dade County Commission's nine-hour bull session to approve the Florida Miami Marlins' new stadium, Commissioner Sally Heyman posed a rather simple business question. She asked what would happen to the ballpark's projected $1.9 billion cost if the municipal bond interest rates went up half a point when the county actually issues the bonds? County Manager George Burgess, who's been heralded as a financing guru, replied: "We're not going to know what th