SPI & CPI Question

hi 

here is a question in EV mgmt 

 

During 4 month project with $4000 budget to be spent evenly on every month. After the second month you spent $3000 and work is 40% complete. What is the SPI and CPI for the project.
 
As per my calculations SPI = 0.8 and CPI = 0.533
 
Can someone please confirm if its correct or not, I think "After the second month" is the key. can it be interpreted as at the end of second month and begining of the 3rd month whats are the SPI and CPI for the project. 
 
I would appreciate your thoughts. 
 

 
BAC=4000
AC=3000
SPI=40%
 
CPI=EV/AC
 
CPI=EV/3000
 
EV=40/100*4000
 
EV= 1600
 
CPI= 1600/3000
 
=>CPI = .533
 
 
SPI = EV/PV
 
PV=50% (End of second month)
 
 
PV=50/100*4000
 
PV=2000
 
=>SPI=1600/2000=0.8