So what im questioning is how sediment layers can be used so affirmatively when they are not always consistent. Would you use a calculator which occasionally produced an incorrect answer?
You are questioning sedimentology and stratigraphy only because you do not understand the subject matter. These processes are predictable, and as was already mentioned, they follow the laws of physics and geology. The fact that you lack the knowledge in how to interpret these deposits is not the fault of Nature, but your own.
As you must be aware, calculators are not the problem -- users are. Same in geology: garbage in, garbage out.
You need to pick up a real geological textbook and start reading.
If the sedimentology and/or stratigraphy do not make sense, it is OUR fault. We need to study the deposits in greater detail to figure out what exactly it is we are missing. Geology is not black and white. It is black and white and a million shades of gray.