Federal Archives and Records Center versus National Archives, regional

I recently went to the National Archives in St. Louis and looked as some flight records from WWII. They are on unpublished microfilm and only available in St. Louis. I was going to cite them like a regional holding (page 480, 4th edition), include the microfilm reel etc., then put the archive where I looked at them at the end.   

Then I saw this other citation for unpublished film where the location information is before the microfilm information. I wondered if I’m not considering something about unpublished, regional holdings, who filmed it or something? 

Here’s the archive portion of the two citations: 

Page 479: NA-Region Unpublished Film

“…; imaged, Federal Archives and Records Center (Forth Worth, Texas) microfilm project AMID 5-004 > roll 81; citing Records of the Central Superintendency, RG 75: Records of the Bureau of Indian Affairs.” 

Page 480: NA-Regional Holdings (this is a manuscript)

“…Pawnee Agency Records, Record Group 75: Records of the Bureau of Indian Affairs; National Archives at Fort Worth Texas.”

 Thank you,

Stacey Cummings