Different formulas for Different Quarter

Hi,

This is my data

if it is 2018 Q1 or 2018 Q2 or 2018 Q3 then sum(Amount) + lookup(sum(Amount),-1)*.5

if it is 2018 Q4 then sum(Amount)+lookup(sum(Amount),1)*.1

Same thing for other years 2019, 2020 (This is sample data .so there is no data for 2019 and 2020)

Its giving me an error when i am using Contains() function to find out Q4.

Quarter  is in String Format.

Please find attached workbook.

Any Help.

Thanks

Pavan Kumar