Many of these cities have more than two purchasing levels -- ie not just regular purchasing vs. competitive bidding.

From the City of Charlotte's Website:

The County buys at three (3) different levels. The first level is anything of value less than $5,000 of which the requesting department has the responsibility and the authority to select the vendor and obtain pricing information. The second level is anything of value between $5,000 up to $50,000; a Request for Quotation is issued to three (3) or more vendors. The vendor exhibiting the best price, delivery, and/or additional criteria is awarded the order. The third level is for products or services valued at more than $50,000, official sealed bids are solicited and electronically posted on the County's website for at least ten (10) days before the dates set for receipt of bids, proposals or replies unless the Purchasing Division determines in writing that a shorter period of time is necessary to avoid harming the interest of the County.

How would be describe these things in here?