This is the resultant classifications, but Vref refers to Flaps 30, max landing weight, no thrust.
The other Vref's, such as Vref20, etc are just that flaps 20.
Due to your aircraft configuration, the Vref will be somewhat variable.
747-400 Operating Procedures Manual
MLW of 297,500Kg (654,500Lbs).
Reference speed for each flap is follows :
Minimum Clean Vref + 100Kias.. 136+100 = 236 Kias
Flap 0............ Vref + 80 Kias...136+80 = 216 Kias
Flap 5.............Vref + 40 Kias...136+40 = 176 Kias
Flap 10............Vref + 30 Kias...136+30 = 166 Kias
Flap 15............Vref + 20 Kias. 136+20 = 156 Kias
Flap 20............Vref + 10 Kias...136+10 = 146 Kias
Flap 30/full...Vref + 0 Kias....136+0 = 136 Kias