Why doesn't the experience from collecting bard chimes scale with game time?

As an avid chime collector, it hurts to hit the 48 minute mark and still not be level 18. You have to give up a TON of lane experience to get chimes, even if you only leave rarely to collect them in large batches. Rather than giving 20 flat xp, what if the xp scaled like this:

xp = 5 * number of chimes collected

With this change, you get less xp for the first 3 chimes (which you typically pick up before laning), then afterwards you don't have to fall so far behind on your magical adventures.