Unskilled checks and aces

[JGun87]

P. 88 of the core rule book for the Adventure Edition says all trait rolls can ace, so naturally I assume if a player rolls an unskilled check (d4-2) and rolls a 4, that die aces like other checks. But do they then apply the -2 modifier to the total just once, or does each additional roll tack on a further -2? Or does the -2 apply BEFORE determining whether an ace happened at all making acing impossible?

[PEGRon]

The –2 to an unskilled Trait roll only applies to the total. So dice of 4+4+3=11–2. That's a 9.