If you have been successful in calibrating one sensor, than the procedure should hold for the second.
Since you have the same 4 volt change over the pressure change from 14.7 to 150 psi, I don't understand the difference in slopes between the two sensors.
One sensor goes from .5v to 4.5v over the range, and the other goes from 1v to 5v. I would think that the slopes would be the same, and the offsets different.
I think you are making the same error with calculating the values for the second sensor as you made with the first one when you originally had the slope as 0.1832844575.