Hi Oquario. Boxes aren't tied specifically to one bank chain.
Coins are packaged (wrapped, rolled, and boxed) at a money room or other processing facility and then driven to the banks by an armored car company (Brinks, Dunbar, Garda, etc). Banks might not necessarily use the same combination of processing facilities and armored car companies at every single location.
The only trend you might see is between BOAs in your immediate area since they will likely use the same money room between them. Beyond that, money rooms, armored delivery services, and banks are mixed and matched so it's virtually impossible to determine trends across the same banks unless you can confirm which boxes come from what specific source.
For example, the design of the boxes or codes unique to the source coin processor can tip you off. Many a CRHer hour has been spent trying to reason out the whys for the ebbing and flowing of the silver.
To sum it up, chance plays more of a role than reason. Good luck!
