Scale a 5 gallon kit up to 7.5 gallons?

[unfairbeef]

If anyone has any input on this, I would greatly appreciate it. I am wondering if I can take a Brewer's Best Australian IPA kit and scale it up to 7.5 gallons. I have a couple ounces of extra hops sitting around and some DME I could use but I'm not really sure how much I might need. Would it be reasonable to just add one half of the existing extract in addition as I am scaling up 50% of the recipe? Then maybe grab a bit more specialty grains to keep balanced? Please tell me if I'm just trying to hard but I want to make a bigger batch as my first kegged batch went pretty fast...

Ingredients
FERMENTABLES
3.3 lb. Light LME
2.5 lb. Amber DME
SPECIALTY GRAINS
1 lb. Caramel 30L
8 oz. Munich 10L
8 oz. Carapils®
HOPS
1 oz. Cascade Bittering
3 oz. Galaxy
1 oz. Flavoring
2 oz. Aroma
YEAST
1 Sachet

 

[Kate00]

Beer recipes are scale-able, so multiply everything by 1.5, or whatever you want to scale to in the future

 

[unfairbeef]

That is the assurance I was looking for, thanks!