|Spades Slick attacking Biscuits' oven with Crowbar's crowbar|
Evidence would seem to be disprove this theory. Crowbar's crowbar (which can destroy objects with temporal abilities and negate any effect they had) seemingly had no effect on it. The comic outright states "[the] oven doesn't really have any magical time properties to be negated".
However, this isn't a completely baseless theory. A bomb set for a few seconds was placed in it. However, the bomb didn't go off until hours later. This clearly proves it has some sort of power over time. Also, Biscuits doesn't react to the bomb. This could be explained as him being in suspended animation due to the halted time.
However, this poses the question why the crowbar had no effect. It could be the crowbar only negates object's time powers if the object is destroyed. Alternatively, the inside of the oven could be the only part with his power. As such, the inside would need to be damaged to remove its powers.