Beersmith - How to calc. how much DME to add?

[Brewme]

When my OG is too low before the end of the boil, I need to add some DME. Anyone know how to calculate how much to add in the Beer Smith program?

 

[Parker36]

Just plug a random amount in there and then you can adjust depending on the outcome (the increase/decrease amount buttons are real handy for this)

 

[Brewme]

The recipe I did today had an OG of 1.081 and Beer Smith was dead on when I initially entered the recipe. But when I took a reading during the boil, I was low so I needed to add DME. If I just added more DME in the recipe section of Beer Smith it would have said the OG was higher than 1.081 but it really wouldn't have been; so I don't think that will work.