The Dungeon Master's Guide provides spell-casting information on the Staff of Power on page 202:
Spells: While holding this staff, you can use an action to expend 1 or more of its Charges to cast one of the following Spells from it, using your spell save DC and spell Attack bonus: Cone of Cold (5 charges), Fireball (5th-level version, 5 charges), Globe of Invulnerability (6 charges), Hold Monster (5 charges), Levitate (2 charges). Lightning Bolt (5th-level version, 5 charges), Magic Missile (1 charge), Ray of Enfeeblement (1 charge), or Wall of Force (5 charges).
Only the Fireball and Lightning Bolt specify that they are cast as 5th-level versions of the spell.
My question is the following:
Since the spell-levels for the remaining spells are not stipulated, are they all cast at their lowest level versions?