But I find the rules as presented unnecessarily complicated. You need to be a specific class level, and then you pay an amount of experience determined by your effective character level. It implies without specifically saying that if you fail to pay off your LA at the indicated level, the opportunity is forever lost to you. I don't like it, and want it simpler and clearer.
Let's consider how much you would pay in the old system. Let's imagine a tiefling, with +1 LA and no hit dice. Once she reaches 6000 experience and dings class level LAx3=1x3=3, she may pay (ECL-1)x1000=(4-1)x1000=3000xp and drop the LA. She is now at 3000 experience, precisely appropriate for her new ECL of 3. The system is designed to achieve precisely that result, never having more or less experience than is appropriate. But I don't care about that so much, so I consider myself free to simplify it without any need to maintain the precisely proper amount of XP relative to level.
UA's system is explicitly set up in response to the fact that, as a character gains levels, his benefit from LA begins to pale in comparison to his class abilities. That's the other part of why they set the specific limits on what levels you can begin to pay off your LA. But I'm confident that this will be achieved to my satisfaction, even if no one else's, simply by requiring you to have enough experience to spend. As a bonus, if you spend all your experience down almost to zero, it will be a long, boring slog before you can increase your level again, which may make players think twice about it.
So we can do away with the restriction on when the LA may be reduced, provided the character has enough experience to do it. We need to change the experience cost to constant numbers, then, and make them depend solely on the LA the character started with. We need to determine, then, what those numbers should be.
UA cares about hit dice. Do we? If so, we need to figure out the average HD of each tier of LA, which adds substantial scouring of the Monster Manuals and extra calculation to our workload. If not, our experience costs will wind up substantially lower than UA's. This could easily go either way, and perhaps in the future I'll make another post, doing the necessary calculations to take HD into account. For now, I'll pretend all creatures have class levels and LA, but no HD.
Let's consider our tiefling again. She may spend 3,000 experience to reduce her LA from +1 to +0, so that makes a good starting point:
+1 : 3,000
What would a LA+2 creature like a drow need? Well, the drow dings class level LAx3=2x3=6 at 28,000 experience, and may reduce his LA for a cost of (8-1)x1000=7000xp. He is now ECL7, with 21,000xp. At 45,000xp, he dings class level 9, ECL10, and may pay (10-1)x1000=9000xp to reduce his LA to zero, leaving him with 36,000xp at ECL9. Thus:
+2 : 7,000; 9,000
Long story short, the complete chart up to LA+10 (if you have LAs higher than +10 in your game, consider the possibility that you are some kind of crazy person) winds up working out to:
+1 : 3,000
+2 : 7,000; 9,000
+3 : 11,000; 16,000; 18,000
+4 : 15,000; 23,000; 28,000; 30,000
+5 : 19,000; 30,000; 38,000; 43,000; 45,000
+6 : 23,000; 37,000; 48,000; 56,000; 61,000; 63,000
+7 : 27,000; 44,000; 58,000; 69,000; 77,000; 82,000; 84,000
+8 : 31,000; 51,000; 68,000; 82,000; 93,000; 101,000; 106,000; 108,000
+9 : 35,000; 58,000; 78,000; 95,000; 109,000; 12,0000; 128,000; 133,000; 135,000
+10 : 39,000; 65,000; 88,000; 108,000; 125,000; 139,000; 150,000; 158,000; 163,000; 165,000
Most of these do indeed allow you to pay off your LA much earlier than UA would allow. Heck, an LA+10 creature needs 66,000xp just to ding class level 2, so it could pay off its first point of LA before it ever levels at all; UA would have it waiting until class level 30 (ECL40). Conversely, paying off the LA before level 1 does almost double the amount of xp it needs to earn before it gains a second class level.