Replying to Armada Edollo in 188cm, too long?

So, recently i asked for advice on my Ski lenght.
I am 186cm and was adviced to buy 188cm Ski.

I have read some articles now about ski lenght, which say that especially for park
(which i aim for mostly of course, with the Edollos) i should take shorter Ski.

Mine are now +2cm.
I didn't put any bindings on these Ski and i guess i could still sell it for the original price.
So, i am now thinking about selling the 188cm and go for the 178cm, which would be exactly 10cm shorter than me.

What do you think about that? I will ski 80% Park and 20% Pow, maybe more often if the conditions are perfect.