Commision rates and conditions differ from Composer to Composer.
Usually, the commissioner will not be charged for typesetting or printing unless the work is to remain unpublished, the composer may feel that a typesetting fee is appropriate, again these differ, but usually expensive.
As far as BASCA are concered, this is a composition commission, they also state that this is a minimum or 'standard rate' figure and that it in no way reflects as a maximum, indeed there is no maximum.
I charge differant rates according to the instrumentation, but regardless of the instrumentation used, the same amount of harmony, counterpoint and melody is applied, this should be remembered, as a work for String Orchestra would probably cost just the same as a Piano work - perhaps the composer may add an extra charge for printing, I know that I don't.
In terms of copyright, the composer (or publisher) keeps the copyright and can release the work commercially, but a 'comment' or 'dedication' should be marked on the score and parts. With Film and TV commissions, copyright is handled in a different way and usually the composer will not retain copyright.
I think it is very doubtfull that a Brass Band composer would 'hand-over' the copyright of the work. Copyright is a property right and just like any other property it can be bought and that ain't cheep. If a company or whatever came up to me wanting to buy the copyright of a couple of my pieces, then the figure is going to be around £5,000,000. Which, may sound ludicrous, but the possibility of getting your money back 20 times over on the two pieces is there if you know how to make the most of the music.
Anyway, although fees and terms differ somewhat, I think it's safe to say, that in the Brass Band world, u'll only have to pay for the composing of the commission. All I can say is I charge £300 per minute of music, that inludes the whole lot - composing the commission; typesetting and formatting; fully published (digitally) printed set; The right to have first dibs at recording the work with no fee attached; 'dedication' statement of who commissioned the work.