Document is Running VERY slowly ... Too many equations to process?

Attached to this post is a copy of an electronic timesheet I have been developing. There are many nuances that go into our organization's schedule resulting in a lot of formulas. I just now began experiencing a sluggish document and have no idea why it is being slow. If you type in a time such as "1500", VBA code automatically converts it to 15:00 (representing 3:00pm). You will notice that there is a significat delay when you type in a time and hit the tab or arrow button to go to the next cell. Any light anyone may shed on this issue is greatly appreciated!

Without getting into the merits of the models design you should note that Conditional Formatting is super volatile - the sheer volume of rules in place is the main culprit.

To illustrate - if you run the below code (removes all conditional formatting) in a back up version of your file and then test the subsequent performance you will (I think) notice the difference.

Sub Remove_CF()
    Dim ws As Worksheet, xlCalc As XlCalculation
    On Error Resume Next
    Set ws = Sheets("0703")
    With Application
        xlCalc = .Calculation
        .Calculation = xlCalculationManual
        .EnableEvents = False
        .ScreenUpdating = False
        ws.Cells.SpecialCells(xlCellTypeAllFormatConditions).FormatConditions.Delete
        .Calculation = xlCalc
        .EnableEvents = True
        .ScreenUpdating = True
    End With
    Set ws = Nothing
End Sub

I suspect you can revise your rules if you need the conditional formatting but I imagine from my initial glance there are other gains to be had by virtue of a re-design.

Thank you for taking the time to look at my project. I will attempt your solution, but I am fairly new to VBA code and may have additional questions. Thanks again.

To be clear - the VBA is not a "solution" per se - it is merely to illustrate that the Conditional Formatting is the cause of the slow down [by removing all the rules you will see the difference in performance]
On that basis: run on backup version

In terms of resolution - you will need to revisit your Conditional Formatting requirements and/or configuration.