LOL...yeah, you are right, may not be the easiest thing to decipher.

OK, so let me walk through a "how to" use-case.

Take a look at the attached image, I will point out how all these different elements are related to each other.

1) 2159 Metereing Rod TAB
- this '2159_Rod' TAB simply has the setups to allow you to assess/compare the various primary jet size changes and how they impact the overall fuel supply when compared to a BASELINE SETTING

2) BASELINE SETTING
- in that sheet you will find the table which shows 'BASELINE SETTING' in the top left corner
- you will see that in this case I am using a 75-2159 rod, 120-4098 primary jet (0.098) and 120-5143 secondary jet (0.143)
- I highlighted that using the RED highlight

2) "what if" comparison
- now when you look at all the other tables in that TAB, you will see that they show the same rods but with different primary jet sizes
- in the image below you will see that I'm now comparing the BASELINE settings to the PRIMARY JET=0.092 (BLUE highlight)
- the changes are all shown as % differences from that BASELINE setting and are highlighted in GREEN
- for comparison I include the same BASELINE rod in this table (highlighted in RED) which when used with the smaller primary jet shows the % changes to the fuel supply (highlighted in RED)

3) remaining tables...
- as I mentioned above, these just show you the same kind of comparisons but across various other PRIMARY jet sizes

Now, all these TABs are kind of static, meaning that they only account for changes to the PRIMARY jet sizes. Of course you can adjust the SECONDARY as well, but that's a change you have to input into each table separately.

Instead of doing that, if you look at the 'Comparison' table, you wil find the same BASELINE SETTING table as well as 9 different "what if" scenario tables. In these tables you can input any combinations of sizes of rods, primary and secondary jets. This is the dynamic part of the calculation, while the other TABs are pretty static, which allows me to do a quick "what if" assessment for a known metering rod that I'm already using.

Alright...so does the above explanation make it better, or worse actually??? LOL

It is for this reason that I thought a cell phone app would be so much better...

NOTE: Oh, important to point out the following: all these '% change' are calculations of the area change that the fuel is passing through. So I'm not actually just comparing a simple measurement (diameter of the jet opening), instead I am calculating the area of that opening, and then comparing the new area to this original one in order to see the '% change'. I did that because the parts here all have a circular shape (jet opening, rod cross-section, etc.), so I needed to see the real area of flow available to the fuel passing through this opening.