I was testing the character generation system by building an elderly magus season-by-season. The magus was experimenting on a healing spell just at the limit of his ability to invent. By luck, I received several Experimentation: Extraordinary Results: “duration, target, or potency is increased”. Now, this was a test, so neither the character nor his spell will every be used in a campaign, but it does bring up some questions.
If, through experimentation, a spell's duration, target, or potency (or overall power) changes, does the spell's level also change to match? Does this happen immediately (changing how long it will take to invent the spell), or is it applied after the spell has been invented? If immediately, what happens if a magus gets the result on their last roll, the one that should have invented the spell, but the result makes the spell harder to invent by enough to delay it (or prevent it entirely)? Several of the Side Effect results can produce a spell with different requisites. The example major flaw (see ArM5 pg 109) might add a Perdo requisite, the example major side effect would get an Animal requisite, and the example major side benefit would add an Intellego requisite. Does the final spell get the additional requisites? What if it needs them only to express a major flaw? Do the new requisites change the Lab Total for inventing the spell?