How to adjust a knitting pattern

Hello everyone. I’m new here! Nice to meet you all.

I knitted a blanket for my son when he was born and now looking to knit one for baby two.

The finished size first time round was a bit small so I’m trying to make it again, but bigger. In the image, I’ve written out the original pattern and then how I think I can make it again, but bigger. Can someone please take a look and let me know if that looks like it will work, or if my maths are completely off?

Thanks in advance!

Welcome to KH!
Congratulations on both babies. They are a wonderful incentive to knit.
Those numbers will certainly work. You might consider the size of the inner square and perhaps make it a bit larger. The blanket is going to be a bit shorter rectangle than the first assuming this is all worked on the same yarn and needles.
The ultimate design however, is up to you and the way you would like the blanket to look.