Kona Dew Drop -- sizing question

Satu

Hi everyone,

I'm looking at buying one of these, but am now getting confused about sizing. On this website it says:

The Dew models have a compact frame size that come up 5cm smaller than stated. E.g. 56cm frame = 51cm

So (forgive me if this is a stupid question :P) does that mean that I would need a bigger size than I'd normally get, or is this just a technical bit of info?

I'm 5'4", and I've got a 51cm road bike, but suspect a slightly smaller one would be more comfy.

Any advice, please?

Cheers,
Satu