While transforming EEBO-TCP texts into P5, I have come across many instances where the P5 model for postscript is inadequate. <postscript> does not permit opening and closing elements. But it is not uncommon for a postscript to be a microversion of the letter to which it is appended, with some form of "Dear Sir" and some form of "Sincerely yours, John Smith." Opener and closer elements would be welcome. Right now you would either have to downshift the encoding to <ab> or turn a more complex postscript into floatingText. Neither of these is an attractive solution.