Parsons (vicars or rectors) always had a house for their use but income was dependent on other factors - maybe fields rented out, tithes and duties etc. In older records one would find the value of a "living" quoted, e.g. "£1000 per annum" (if they were lucky!!) but whether that included an assessed value of the rent for the house I am not sure - I have a feeling that it did not. The differing values of the "living" was the reason why many people held two, or maybe three, "livings" in the 18th-19th centuries. Because they were allotted through various forms of patronage if you got in with the right patron, it was possible to be quite well off - even if the parishioners of two of your parishes only saw you once a year. Or you employed a poor curate to do the work at a pittance. You are however, on the right track, a "living" was basically the income received by the incumbent of a parish - vicar or rector. Good luck with it.