Hello Tom,

A 16 x 4 line LCD only uses ONE 44780.
After initialisation, the addressing is:
Line 1: $00->$0F
Line 2: $40->$4F
Line 3: $10->$1F
Line 4: $50->$5F

Please find more information I wil sent you in your e-mail box, 2 PDF-files with all you want to know about different size LCD's with 44780 controller.
Have Fun :)

Henk