According to some customers' description, for example: if your reading glasses is +2.25, and driving glasses is +1.50 OU that means your ADD should be +0.75 instead of+2.25.
Currently, the optical company could only provide bifocal lenses with +1.00 bottom power (ADD).
When you use it for reading, please move the objects a bit further. (+0.25 will not affect any discomfort for reading use, do not worry)

Thanks for your information. I prepare to buy bifocal eyeglasses for my father, the power of his reading glasses is +3.00 and the power of his driving glasses is +1.75, if you mean ADD of his bifocal glasses should be +1.25??