It seems the simulation just gives the upper bound and lower bound based on the input ranges. A spreadsheet model can do the same thing by running the model with different input ranges. In fact, that's what a spreadsheet model is for, trying different input to run what-if scenarios.
On the rental investment example itself, it would really help to have a finance person to go over the model. A rental investment needs to be modeled like running a business, not like buying a house to live. Its analysis is usually done using net operating income, CAP rate, cashflow, ROI, and IRR.
BTW there's no magic 1% to 4% annual appreciation in rental investment. Appreciation is purely based on increasing net operating income faster than market rate, or in simpler term improving CAP vs the market CAP rate. Let's say you buy a property with 4% CAP rate and the market CAP rate is 4% now. 10 years from now your NOI still produces the same 4% CAP but the market CAP rate has risen to 6%, your property will depreciate! Market CAP rate is affected by different things that're out of your control and it's hard to model.
On the rental investment example itself, it would really help to have a finance person to go over the model. A rental investment needs to be modeled like running a business, not like buying a house to live. Its analysis is usually done using net operating income, CAP rate, cashflow, ROI, and IRR.
BTW there's no magic 1% to 4% annual appreciation in rental investment. Appreciation is purely based on increasing net operating income faster than market rate, or in simpler term improving CAP vs the market CAP rate. Let's say you buy a property with 4% CAP rate and the market CAP rate is 4% now. 10 years from now your NOI still produces the same 4% CAP but the market CAP rate has risen to 6%, your property will depreciate! Market CAP rate is affected by different things that're out of your control and it's hard to model.