Owner - D20 Hobbies
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No for two reasons.
Similar things don't stack, so like two castings of Strong Jaw won't stack and two different things making your damage dice bigger the same way, won't stack.
Also, one doesn't stack with Extend Spell "or similar" and the other doesn't stack with Extend Spell. They both work like extend spell, so it was clear they didn't want increased duration effects stacking.