Don't do that with me,
You said 1-4 months of income you didn't say anything about wages
The list includes wages but you didn't both to read either source. Wages are a form of income.
Second I asked for reference for jizia being 1-4 month of income not for units and price list is Europe
You asked for a reference that does not exist as I am comparing the value of the coin to what the middle and upper classes earn. You request in irrelevant. More so you tossed out your own math without any reference to a person's income at all. Hilarious that you demand from what you should have provided yourself. Do you know what a dirham is? Do you know how much it is worth? Do you know what people earning back then?
Also you are wrong as the poll tax is in dinars (gold) not dirhram (silver), according to Reliance of the Traveler.
Look up what a dinar is, its composition and weight. Compare it to the shilling's weight and composition. Gold coinage in Europe didn't become mainstream for centuries. With this value in mind reference what one can buy with a shilling and lower in the list regarding wages. For example a weave (middle class) earns 5 pence a day. This is without food or other costs such as housing, taxes (when called). Look at the price list as a weaver does not produce their own food supply like a farm. Consider what foods they can and can not buy. For example cheap wine per gallon would cost the weaver most of their daily income. Look at the costs for craftsmen renting a place of business which typically include housing in the rear part of the business front. Do some basic math. You should quickly realize how much money is spend on basic needs leaving little for any savings for you tax.