Adding 5.5lb of LME will add ABOUT .6 gallons of liquid?

IS that about right?

If one gallon = 8.34lbs then 5.5lbs = .659 gallons?

SO - Instead of using 5.5lbs of LME I substitute 4.4lb of DME I need to make up .659 gallons of water somewhere . . . . . . .right?

From the last couple I've done:

9 lbs. DME increased volume by ~1 gal.
12 lbs. DME increased volume by ~1.25 gal.

I haven't done any measurements with LME. How much volume is 5.5 lbs. LME?

EDIT: looking at various sellers, 6 lbs. LME comes in a half gallon bottle. 5.5 lbs. LME in that case would be about 0.46 gal.
4.4 lbs. DME would increase volume by ~0.46 - 0.48 gal.
Basically, it looks like you don't need to add water when converting from LME to DME.