if you step outside the rules in the slightest many companies are very quick to challenge and threaten legal action
And, while some organisations on the catalogue are capable of being flexible, some of the bigger ones very much take a "this is what we offer and we won't vary" simply because of their market power. And, sadly, a lot of the smaller companies seem to have senior managment who have worked at the larger outsourcers so they repeat the mistakes of the big organisations at a smaller scale.
Which is why some things get insourced after years of being outsourced.
Biting the hand that feeds IT
