I'm so happy to finally see pictures, and they look better than what I was expecting.
Teacher style is often most baffling to those of us who are teachers but have no interest in little red-school house embroidered sweaters or wooden yellow pencil jewelry.
As SWTXBelle noted, dressing professionally and appropriately for a job with a lot of random duties is more challenging than you'd think, and jumpers, any time you can sort of fashionably get away with it (these things do seem to have a cycle) make sense.
But it still doesn't explain this:
http://www.homeroomdirect.com/product.html?t_q=CR541