Problem with NORMSDIST and distribution of hours

Good morning everyone,

This is my first post in this splendid forum. I'm sure I will learn many things here.

I'm sorry if my first post includes a question!

Let me explain what is the problem.

I made the below spreadsheet in order to distribute a generic sum of hours (making a bell curve more or less) for a standard project by disciplines (Engineering field).

As you can see there are also 2 percentages (Go and Get) that balance the hours.

I don't understand why the sum of the distribution in BD53 doesn't exactly reflect the hours in B6. Any ideas?

Many thanks