[D&D 4E] Character sheet problems

Hi I'm having problems trying to use the 4E character sheet, I noticed that some of the values are derived from others and cannot be touched (such as bloodied and surge value, as they are 1/2 max hp and 1/4 max hp) but I'm trying to build a character sheet for a PC and I noticed the Fort Defense was wrong. He has 18 str, 16 con, but in 4E, it takes the higher of the 2 for the Fort defense, but it seems to not do that on the character sheet, and there's no way I can directly change it.  I would like to understand what's going on here. Please and Thank You

This is something commonly missed on the 4e sheet. Because there are certain benefits which can alter the ability used for a given defense, simply calculating the higher of the normal two abilities is not sufficient. Therefore, the sheet author included a means to select  which ability to use. Click on the settings tab at the top right of the sheet, and then scroll to the bottom. There should be a section (it might be collapsed, so you might have to click a button to expand it) where you can pick which ability is used for each defense, initiative, etc.

Thanks, Brian! I ran into this same problem re: defenses. :)