I saw that A&E show on the Gambinos. "Crew" is not synonymous with "regime." Gambino had two capos--Paul Castellano, in charge of "white collar" operatons; and Aniello "Mr. Neil" Dellacroce, who headed "blue collar" work. Each had multiple crews under him. The show often referred to Gotti, on his way up, as a crew chief under Dellacroce.
Each of the Corleone capos could have had many crews under him. Tessio had enough men to have 50 of them guard the mall after the Don died.