Weapon of light shield refresh issue

[Elkan]

Its a bit of an edge case, but if you have a sun paladin with a large number of attacks (Say using Dethlok, with flex and Shield of light) you are looking at a minimum of 5 attacks a round, and 11 when using assault just form basic abilities. The problem then comes that it becomes impossible for any damage shield to hold up more than 4 turns, and will frequently break in two due to the refresh limit of 20 refreshes, forcing you to choose between abandoning damage shields, or weapon of light, both of which are intrinsic to paladins, and designed to work hand in hand, rather than excluding each other.

I would suggest an amendment to the shield overloading mechanic in which the shield will shatter when either

The shield has been refreshed/enhanced 20 or more times AND its original duration has elapsed

or

The Shield has been refreshed/enhanced on 20 different turns.

Which applies depends on what you envisaged the limit to do. if the 20 turn cap was just to prevent massive damage shield climbing on soft targets dummies, or extending the elixir of invulnerability forever then go with the second option.
If multiple attacks were envisaged in the skill and it is to prevent the shield being increased too much, then option A would be best.
I find it hard to believe that having shorter than usual durations for damage shields was an intentional consequence, given the relatively low power added, in comparison to say bathe in light. (whether or not the latter skill is balanced is contended by some but beyond the scope of this post)