@JeremyECrawford Metamagic rules state you can't use multiple Metamagic options on a single spell. Can you use one option, multiple times?
— Revenant_Fury (@Revenant_Fury) August 7, 2015
The intent is that a sorcerer can use a Metamagic option once with a spell, not the same option more than once. https://t.co/7iofA0d62k
— Jeremy Crawford (@JeremyECrawford) August 7, 2015

But in the case of extended spell, can it extended until the 24h limit obout the metamagic?
I’m wondering the same, like obviously you can’t twin multiple times, but if I’m willing to expend all 6 sorc points to push shadow blade up to an hour, where’s the harm?