Question

how to compare myselfs iodine number values to published values, for butter, i got 23; for coconut oil, i got 4. but published values are a range: 26-40 and 7-10

Answer 1

Iodine value is  used to measure the degree of unsaturation of oils and fats.

The results are usually expressed as number of grams of iodine absorbed by 100 g of oil or fat.

Iodine value determination usually by a titration , such as the Wijs method (using solution of  ICl : iodine monochloride  is used for double-bond saturation analysis).iodine value are in direct proportion to the number of mono- and polyunsaturated bonds within the constituent fatty acids

Reported values for coconut oil are in range of 6-11 : your value is 4. : possible explanation if you have not committed any experimental or calculation error than is : is loss of unsaturated  fatty acid and a decrease in the iodine value of oil might be due to as it promotes intensive thermo-oxidative transformations or sample was quite old so, rancidity might have (as Unsaturated fats are more susceptible to oxidation than are saturated fats ) occurred.

Reported value for Butter is 25-42 :: your value is 23 : it is not much deviated from published value , your source of butter might be from more saturated fat .