Smart Plug 30A

Back of Pin Contact = 16.4mm X 8.5mm = 139.4 sq mm
Front of Pin Contact = 6mm X 8.5mm = 51 sq mm
Total Contact Area = 190.4 sq mm

30A Twist Lock

Back of Pin Contact = 1.3mm X 2.7mm = 3.51 sq mm
Front of Pin Contact = 1.3mm X 2.4mm = 3.12 sq mm
Total Contact area with dimple locked in place = 6.63 sq mm

Disclaimer: Due to the curved shape of the twist-lock measurements are as near as can be made, with a caliper, without going to impressions on transfer paper. The Smart Plug pins are flat thus measurements are far easier.