There are several cards in the game that seem to set a value "at" a base value plus some number. Are cards that use "at" a replacement value even though they also use the "+"? Most of these cards would be activated during fleet building and seem to be setting a new value rather than a running variable during gameplay.
Assault Vessel Upgrade:
"You may fill any slot on your Upgrade Bar with this Upgrade. Your Primary Weapon and Shield values are at +1. This Upgrade may only be purchased for a Bajoran Scout Ship and no ship may be equipped with more than 1 Assault Vessel Upgrade."
Combat Vessel Varient:
"Your Primary Weapon and Hull Values are at +1. In addition, add 1 Upgrade slot to your Upgrade Bar. This Upgrade may only be purchased for a Suurok Class ship. You cannot deploy more than 1 Combat Vessel Variant Upgrade to any ship."
Systems Upgrade:
"You may fill any slot on your Upgrade Bar with this Upgrade. Add 1 icon to your Upgrade Bar. Your starting Shield Value is at +1. This Upgrade may only be purchased for a Federation ship and no ship may be equipped with more than one "Systems Upgrade" card."
Thank you