Calculation Cash flow

Hi Experts,
I'm looking formula for cashflow, there are 2 logic, as mentioned below. (file and screenshot attached)

1-LOGIC: (highlighted in yellow)
When new annual rent (B12) kicks in after years of current lease left (B15) expires, the new rent (B12) kicks in. In this example in Year2.
Whenever a new rent kicks in, a compounded growth formula factor is applied to the previous rent base (eg. G4 & G7) and kept constant for another 3 years (currently defined in B14)

2-LOGIC: (highlighted in green)
As gross rental is for the whole year, some years could be made up of a combo of old and new lease rents, For eg. In Year2, as old lease expires in 0.5 yrs, would need a weighted average of 0.5*previous annual rent + 0.5*new annual rents (eg. H4 & H7), Otherwise, constant implied growth rate * Base rent.

Thanks in Advance.
gul