Something like that, though it's not exactly that they are lots more work scoring, but more like they're not as easy to score on the fly. For instance, if you have to add up a lot of items with a wide range of possible points, it's a little slower than when the possible item scores are only 0 and 1. Also, littles usually take closer attention during test administration, so she was probably more occupied keeping your DC engaged.

...pronounced like the long vowel and first letter of the alphabet...