If you make HSTs from your 5" charm squares, they will square up to 4 1/2". Patterns with a mix of HSTs and regular squares will need the regular squares trimmed down to 4 1/2" so that they can be joined.

This is my best guess, without knowing what pattern you're looking at...

Jennifer beat me to it! If you combine a charm square with a pieced unit made up of other charm squares, like half square triangles, 4 patches, etc, you will need to cut the full ones down to match the size of the pieced units. The pieced units will be smaller because of the seam allowance. It all depends on the pattern if you need to trim them to a smaller size or not and what that new size will be. I really don't think it has anything to do with pinked edges.

Go to youtube and type in Go cutter. Tons of videos.

also, on their website.

I learned the hard way that pre-cut jelly rolls aren't accurate. Had to cut over 80 to the exact size.

Ditto! I once bought a charm square pattern for a table-runner (I hung it on a door). I loved the pattern design and would use it again, but the Tonga Treats charm square pack had some oddly cut not-quite squares, and more the pity, the pattern assumed I was playing with a full deck, so to speak :( so I couldn't even use the color combinations I wanted without buying more of the stuff. NEVER AGAIN!
I am not charmed!

I brought a pattern the other day that wanted a 6 inch charm square... has anyone ever seen that?

Yes, I have and I even have a pattern for a 6 1/2 charm.

If I had a pattern that called for 4.5" squares, I'd cut my own. My thrifty nature would not allow me to willingly waste that much fabric from charm squares. I just couldn't do it. LOL

Got charm squares...be sure the latest Missouri Star Quilt Company tute for "PLUS" quilt pattern. I am going to try this next.

Could it be that the pattern you are looking at require the smaller sizes?