While any unbid position in any base is available “for” new hires, the company can pick what to offer “to” new hires. Each class has a specific set of options that the company posts for them to bid on. Traditionally NYC is the least desirable base and also the hardest to staff, so they constantly need to throw as many new bodies in there as they can. They know that almost every new hire put there is going to bid to other bases as soon as they’re able, which continues the vicious NYC staffing cycle.