[Question] Combat style and experience gain

Hello, I have a question relating to combat mechanics and experience gain. While training Ranged, I quickly noticed that experience gain is based on the monster you kill rather than the hits you land. The interesting part is that I would use SGS to heal, sometimes dealing around 60%+ of the monster's HP bar, and still get all of the experience allocated to Ranged.

I'm now training Magic, and the same mechanism occurs. So I'm wondering if I can abuse this to save money on runes and degradable staves. Using sub-par mage equipment, I could simply splash free spells and land a few paltry hits, and then switch to melee/ranged to actually kill the monster and still gain full Magic exp.

What I do right now is to snipe weakened monsters in GWD (dealing 20% of the monster's HP and still gaining 700+ exp is hilarious), and I'm making relatively good money and EXP compared to how little money and investment I'm putting in. If I can learn how to abuse the combat style switching trick I feel like I won't need to wait for NPCs to be weakened to kill them (maxed melee and ranged stats).