Nice catch

No problem. I wanted to try to use your formula to see my hail damage if I managed to max out my reforges, but ran into the missing reforge and Rosemary Glove values in it so I decided to just test them myself.

In regards to my staff guide. I wrote that while half asleep so the points made might not be the most well thought out, but I'll try to explain my thoughts on the matter.

I'm not sure if you agree with me on this, but I think Thunder is the most versatile magic skill to date. Ice Spear tends to interrupt the flow of battle in parties (and I'm a human... that MP cost) and Fireball is too slow to spam a lot. Luckily, Thunder happens to be the best intermediate spell for a staff as well. The damage boost from the bonus 13%~16% damage on a staff in comparison to a wand is unexpectedly significant (which I now know the reason for from your formula) to the point that it's all I really use if I can get away with it. Now that Counter and Windmill can be instantly loaded, even in one on one situations with monsters with magic ping, I just spam Lightning Bolt and Thunder. With the Demonic Staff, I've been able to critical hit with 1.3k damage bolts and 4k damage single charge Thunder strikes. My experience tells me that this is a significant improvement over wands, though I don't have the numbers for wands anymore.

The last section was written just to point out that the staff has its weaknesses. You'll notice that although I suggested using different wands for different kinds of spells, I didn't explicitly state what situations require what magic spell (except for Ballooning and Rafting) as I expected the reader to decide that for themselves.

I agree that any decent mage should have every wand type, but I also very rarely ever touch my wands. My most used wand is probably the Tikka Healing Wand, honestly. My second most used wand would probably be my MP cost upgraded Crystal Lightning Wand for rafting. Recently, I've been using my Crown Ice Wand in the Snake Energy event to Ice Spear the small fry and Fusion Bolt the big snakes. As for the other wands, I rarely use speed Fireball or wand Thunder. I also don't consider the speed-cast Crystal Lightning Wand to be worth much because it only takes off less than half a second per charge. I suppose that's about 2 seconds of saved time for all 5 charges, though.

tl;dr I spam Thunder and the staff is good at that. I also barely use wands despite carrying every type.