You seem confused as to how to use the Effect Test. The step of the Effect Test needs to be rolled, and the result of the roll is used as the effect. Also you might possibly be confused as to what is the Effect Test, and what is the test to Resist the Effect. Specifically, the Effect test is rolled, and the result of that test becomes the target number the target needs to roll for resisting the effect.
Example: Lets say your WIL step is 6. Lets say your WillForce rank is 5 giving a step 11. When the spell is cast, the caster rolls the effect test, if no WillForce is used then it would be 6+3 step 9. Step 9 is rolled and the result of that roll is the target number to resist the spell. If WillForce is rolled, then the step would be 6+3+5+(optional karma) = step 14 (plus optional karma). That is rolled and the result is the target number to resist the spell.
So to be clear, in the example above, the target number is not necessarily 14. Instead a step 14 test is rolled, and the result of that roll becomes the target number to resist the spell. The result might be 14, but it could easily be ether higher or lower than 14. Also, WillForce is only used by the spell caster, when he rolls the spell effect, in hope that the spell will have a greater effect. It is never used for anything else.
However the Lion Heart Talent can be used by the target of the spell to break out of spells that offer a Willpower save.
Lion Heart wrote:
The adept’s resolve improves, allowing him to use his Lion Heart Step in place of his Willpower Step when making tests to resist the effects of any talent, spell, or ability that allow a Willpower test to shake off the effect.
So lets say the Target has WIL at step 6. Lets say they have Lion Heart at rank 5 giving a step 11. Instead of making a step 6 WIL roll to end the Mind Fog, he could make a step 11 (plus optional karma) Lion Heart test to end the effect.