prefer to place FSMOs on multiple DCs

Hi all,

We have one forest with one empty root domain and one child domain.

We have multiple sites and multiple domain controllers.  Currently, every DC is GC;

one DC in root holds 5 FSMO roles (Schema, domain naming, (RID, PDC and Infrastructure); one DC in child domain holds 3 FSMO roles (RID, PDC and Infrastructure)

should we place FSMO roles into separate DCs in one domain like this link mentioned? (http://www.sole.dk/how-to-place-fsmo-and-global-catalog-roles-in-active-directory/)

Thank you.