Despite the many assumptions, i think in kenyan scenarios, Dada may be ahead of Innocent. Why?
Thinking that you can repay a mortgage in 6 years in kenya is a dream to many.... you will have to have an income good enough that you might not even need a mortgage in the first place. Last month, i enquired on a mortgage for a 4.2m house(inclusive of the plot - of course

). One would need to pay 59k monthly for 15 years. What is the average rent in the area? Kshs17k! Well, ask yourself, how many people will afford to be paying that with this sort of return on investment? And this, is actually the cheapest you can find of houses 35km radius from the city. Make that a repayment of 6 years and you will realise it is not realistic for many.
I doubt you can argue that innocent is saving on rent while dada is paying rent because then you have failed to factor in his opportunity cost of living in the house and foregoing the rental income.....(i would think you need to factor this in prudent accounting of your assets)...