How I made my server free.!!

It’s been about three month since I started using ras-pi as my server and media center. So basically before all this I used to use my pc or recently laptop for Jarvis server and other downloading stuffs. I bought the ras-pi for about 2.5k and ported all my programs and server scripts on it and its running since ie 24×7.
So I used my multimeter and measured the running current through pi which was about 750 mA considering 5 V input and all peripherals attached. So power consumed is about
.750A x 5V = 3.75 W
Again my Macbook used 250W but for reference we’ll use avg power of normal laptops that was about 200W.
Now power saved was 200-3.75=196.25 say 196W.
Considering electric rate at about 6Rs per unit.
We get cost for a month to be. (running 24×7)
196 x 24 x 30 x 6 / 1000 = 846.72 Rs per month
And 846.73×3 = 2540.16 Rs for 3 months.
Which is kinda more than the cost it was bought with. ???? ????

P. S.: Again this is not perfect practical calculation there may be many ups and downs. I ignored the dc adapter transformer losses, also the power consumed by the monitor as it’s only used when needed.