Hi - I can help with the math. Did you obtain the
as fed or
dry matter basis values for the flavor from Instinct? If so, can you share those values (I don't see them posted on Instinct's website - which is pretty normal as most pet food companies don't post it though some do like Weruva and Wellness - but I also could have missed them!).
If you don't have the values, you can contact the company and asked for the
metabolized energy values (ME values are the % of calories coming from protein, fat, and carbs - for your kitty, you would just need the carb value but get all three as they should equal 100%). If the company won't share the ME values, then ask for the As Fed and/or DMB values - if you get these values, you would then plug them into the forumla explained in the post you linked (feel free to DM me if you need help!).
If I had to guess, I think you may have plugged in the Guaranteed Analysis numbers into the formula - but those numbers are not the correct inputs (you must use either
as fed or
dry matter values). Additionally, the GA values only tell you the
min or
max value - meaning for ones listed as minimum, the amount could be higher and the ones listed as maximum, the amount could be lower. This is covered in that link you posted and there's link in there to an excellent article on GA values (and why they aren't awesome for those analyzing nutrition).
In summary, this is why Dr. Lisa's list is so awesome...although getting dated...it's so much work to get the values that caregivers really need!
Hope that helps a little bit