When these bikes were produced they might have had a 60% balance factor. God only knows what most of yours is nowadays with all the after market pistons, rods and bearings. Even replacing parts with OEM components will yield different results due to inconsistencies in production. There is however the slim chance you've actually improved the balance for your particular riding style and ability.
I haven't been impressed by the work I've seen from crankworks. I've seen them take weight off in several places around the crank halfs. At 9, 11, 4 and 7 o'clock from the crank pin. WTF? And none of the material taken off was the same distance from center. And I'm not a fan of welded cranks either.
This is a crank I had balanced by Surf 'N Turf out of Connecticut.
Taking the very parts I run and having the ability to balance them to a 56% factor really helped. It runs smoother everywhere. How so? The original parts must have been far from Honda spec. As the motor was assembled by Service Honda piece by piece. No fault on S/H, but I don't believe Honda's or Kawasaki's off the shelf parts receive the thorough QC inspection they once used to now that they are no longer produced.
Regardless of who's to blame, the only downside to a balanced crank is money. It cost me $375. But it was worth it. It vibrates much less than I imagined a 500 could be balanced to run. Yes it vibrates more at some rpm than others, but overall it runs much smoother than you'd think a 500 could. Big thumbs up!