System segregation confusion (The old Program Cleaning methods)

The old saying always states- In confusion lies profit!! A new term called system segregation better know as Program cleaning is a perfect example of this. Years ago, when I starting inspections in other parts of the country, particularly on the east coast, I started running into "Program Cleaning" on kitchen exhaust systems. What was being done is that the cleaning company would have a system split up in to sections that should be completely done on a regular cleaning schedule (3 month frequency for example) on a rotation having only the hoods done one quarter, different parts of the ductwork done another quarter, and the fans on another schedule. The excuse was to save customers money. What we really found was the most of the companies (actually all of the ones we inspected)were unwilling or unable to properly clean most of the system. The Program cleaning made the entire process so confusing to the customer AND to the cleaning crews as to what was actually being cleaned each time that when we found years of grease in the longer duct runs, they simply gave the excuse "That was on on the rotation this cleaning" We even ran into this excuse after fires. It turned out that many areas were "never on the rotation" and often only the hood, fan, and short areas that could be easily reached were ever cleaned and the system was just as dangerous of catching fire as if nothing was done at all. It also makes it almost impossible to use inspection picture verifications as the pictures sent end up so confusing even and expert could not tell if the job is being cleaned correctly and timely. However, There are cases where very long system might only need to be done only 1/2 way, up to an environmental cleaning unit, or up to a tall multistory vertical run every 3 months with the rest of the system getting cleaned every other time. But, there must be a VERY CLEAR cutoff point completely verifiable that the grease buildup past that point is not exceeding NFPA96 requirements (2000-3175 microns or approximately a maximum of 1/12.6"- 1/8" thickness) between the cleaning cycles. That means that is if the uncleaned section exceeds the minimum requirements for cleaning even as little as a week or a month after the first part is done, it should be on the same rotation as the first part. People will split hairs trying to save money and these long systems have the most potential for hidden catastrophic fire. Fires don't always start at the hood and all this grease needs is an ignition source(Fan electrical short, hot coal, cinder, chunk of burning grease, or a rag bouncing up the duct before stopping in the built up grease to ignite it, etc) to start up. If the hood is cleaned, but the duct is not, it can burn hidden until too late to save life or property. I have always been very much against program cleaning as in my opinion, it leads to confusion and has long been a way for companies to simply get away with not properly cleaning the systems. It often leaves a system or systems in just as much danger as not doing the cleaning it at all.