Can you cast a better version of a 1st level spell?

[Burn56]

So I have this 1st level spell: Unbreakable Heart (pg 296 ISWG)
It's duration is 1 round per level, and I am level 7.
So that's 7 rounds. Now being a 7th level oracle, I can cast 3rd level spells.
That being said, the purpose of metamagic feats are for casting spells at higher slot levels for better effects.

But couldn't I create the same spell (with my GM's permission), as a 2nd level spell, and just increase the duration to minutes per/level, or at 3rd level, have it be 10 minutes per level?
I isn't that kind of the point of spell creation?

Maybe I'm just off my rocker.

[Quatar]

Well considering that the Extend Metamagic allows you to double the duration (making it 2 rounds/level), AND requires you to take a feat for a +1 spell level (making it 2nd level), I as a GM would be very very careful to allow you to create the same 2nd level spell with a 10x longer duration instead, without requiring a feat.

[Drakkiel]

When making spells up you are supposed to be careful not to go above and beyond a spell that has similar abilities and such, making the same spell with a higher level also increases the DC, and as Quatar said just to get it to 2 rounds/lvl you have take a feat and up the spell slot so for this specific need as a GM I would say no.

[IejirIsk]

and sure, you can cast flashier spells, but you can cast that one, more often (assuming there is need.) which is better, 2 fireball, or like 4 MM ...