Confirmed Already . . .
The school ties in PoA IS different:



Here's a more enlarged picture of it courtesy of Lauren

So that makes Yellow/Dark Yellow & Red/Maroon Strips of 2cm each & Thin Yellow/Dark Yellow Stripes of 1cm for the Ties.

Now I highly doubt I can reuse my Myrtle's Tie as my Slytherin Tie (assuming Slytherin will be Grey, Green & Thin Grey). >__<