thieves' tools how exactly do they adjust the DC

[Ckorik]

Under Open locks:

Quote:

The DC to open a lock depends on the lock's quality: simple (DC 20), average (DC 25), good (DC 30), or superior (DC 40).

If you do not have a set of thieves’ tools, these DCs increase by 10.

Under Thieves' tools:

Quote:

This kit contains lockpicks and other tools you need to use the Disable Device skill. Without these tools, you must use improvised tools, and you take a –2 circumstance penalty on Disable Device checks.

Which is it - or is that supposed to be cumulative - and if so why not just include it in one place? It doesn't make sense to have a double penalty.

[Jiggy]

That does seem weird at first glance. My best guess is that the -2 for improvised tools applies to ALL uses of Disable Device, while the +10 DC is only for opening locks. Seems, then, that when you're opening locks you'd get both the penalty and the DC increase.

[SlimGauge]

Disable Device is used for sabotage and other things in addition to opening locks.

[Daniel Thrace]

Specific Rule overcomes a General Rule. I would say +10 is all you would add but have nothing more than first thoughts to support my argument.