Is the phrase 'have something down' the same as 'have something down pat'?

Once we have the functional mechanics down, we’ll customize the display of fields using properties and then using richer data templates for the edit, add, and display modes.

This sentence is extracted from a tech book titled 'Silverlight 4 in action'.

I disagree with @wfaulk. It's not "the exact same thing." To "have something down" means to know it. To "have something down pat" is to know it perfectly, as @FumbleFingers points out, though he balks at giving any explanation of the former expression, which is in wide use (at least in the USA).

There is a difference, depending on the tolerances involved in the domain, but I would take "having something down" to mean being able to do a thing merely to a reasonable degree, not flawlessly. At least the meaning may descend to that level; you could mean you know something perfectly, but you could also mean you simply know enough about it to pass some essential requirements.

To have [something] down pat means to have understood or memorised it perfectly. It's generally used in a rote-learning context, rather than one of the subtasks within a software project.

I suppose some people might use the expression without the word "pat". I'm not familiar with that usage - but it sounds like to have something done (i.e. completed), so that's how I'd interpret it.

LATER: The word pat itself has a wide range of meanings, including exactly or fluently memorized or mastered, as in "He recited it [off] pat". It seems reasonable to suppose the usage have [something] down without "pat" is simply a "watered-down" version of the full form, that avoids explicitly alluding to the complete,perfect connotations of that word.

I would argue that the two phrases have mostly the same meaning.

That said, I would say that "down pat" more implies something memorized as rote, and would not be used with a more abstract thing, where just "down" might be.

"I've got the Declaration of Independence down pat." — fine.

"I've got the Declaration of Independence down." — fine, if a little odd.

"I've got the General Theory of Relativity down." — fine.

"I've got the General Theory of Relativity down pat." — quite weird

Also, I might argue that "down" without the "pat" might be more forceful than with. I've used it to mean a full and complete understanding, where as something that is "down pat" is merely memorized.