Sorry I didn't get back sooner. Here is an example of one I recently bid using round figures:
Misc Mat      160,000
Fixtures       120,000
Gear             50,000
Sales Tax      27,000
Total Mat                           357,000
Equip                                  10,000
Subs (Fire/Ground/LPS)        60,000
Direct Labor (4500 hrs)      120,000
Indirect Labor                      10,000
Sub Total 1                        557,000
OH @12%                           66,840
Now, right here my margin dollars/man hr is $14.85 (66840/4500 man/hrs)
(I miss-used the term previously by calling it "profit dollars/man hr". It's the overall "margin" dollars
which includes overhead)
With the overhead added, my raw cost incl OH is 623,840, with no profit.
In a good economy, I can get $25 margin dollars/mh, but now I'm settling for 
less, like 20-22. So to achieve $22, I look at a 5% profit markup which puts my sell price at
$655,032 (margin dollars are 66,840 OH + 31,192 profit/4500 m/h).
So my margin dollars/man hr is $21.78, which is acceptable.
The reason I look at this ratio is, say the owner wants to furnish the fixtures.
That puts my cost at 397,000, then 12% OH+5% profit only gives me a $15.52
margin dollar/man hr. That is when I have to mark up my profit to 12% to get my margin dollars to $22.44.
This is how I cover my labor risk.
I hope this make sense.