5.5 times? I dont think so.

Assuming a 10k Facist Farmer with 200% Agri tech (Normal Tech amount that a farmer should keep during mid set)
Food Production : 5.3 * 10000 * 1.15 * 2 = 122k food

A 10k Facist Oiler
Oil Production : 10000 * 2 * 1.75 = 35k Barrels

So 122/35 = 3.5 times.

Assuming food is at $50 (with above example), one turn will get you $6.1m cash.
6.1m / 35k = $175 / barrel

If food prices is at $50, your oil must sell for at least $175/barrel to be making the same as a farmer with 200% agri tech, not $242


For early set sake(assuming farmers have 0% agri tech, ><)

3k Facist Farmer : 5.3 * 3000 * 1.15 = 18,285

3k Facist Oiler : 3000 * 2 * 1.75 = 10,500

18,285/10,500 = 1.75 times

You would just have to sell oil for 1.74 times of food prices ($35 now) = $62 to be producing as much as a farmer.

You are expecting too much as an oiler.