Rental Calculator Question and advice needed

[Joanna Mendoza]

Hi, we're about to buy a house, move in there, and have our current house rented. When I put in the values of our current house in the Rental Calculator, it says "low confidence". I am not really understanding what that means so I appreciate if someone can explain it to me patiently. Does that mean our property is not a good rental property? Inversely,  does a high level of confidence mean that a property is  a good rental property to buy? 

The house we're buying to transfer to is in pre-construction and is estimated to be finished in 6-8 months. Do we vacate our current house by May to list it for rent by June or do we stay here until the new house is finished? If we list it by the time the new house is finished, will people still be renting around December?

Thanks!

Jing

PS: We're fetuses in terms of real estate investing knowledge...