Rogues are my favorite character class to play, and I have played with the default trap system in NWN since its inception, but have little experience with the specialized trap crafting system in PoTM. That said, there are a few observations that might help.
First, the module creators can set the various DCs of the trap system to whatever they want -- this aspect of the game is entirely customizable by the builder, so it is not unusual to have traps that depart rather drastically from the standard template. That said, I agree that a customized trap system should not create traps that are dramatically inferior to the default traps, while simultaneously allowing purchase of default traps. This would create a huge disincentive to anyone from crafting traps.
Second, the DCs in your screenshot would seem to be correct and not bugged in any way. For any trap, default or custom, the base "set trap" DC is going to be different from the final "disarm" or "recover" DC. The "set trap" number is fixed (either default or custom). It won't change relative to your skill level. However, for a trap that a PC sets, the disarm/recover/detect DC will be relative to the setting PC's skill level. Thus, in your example, the builders decided to make the base detect DC of your magical trap as 16 plus whatever the PCs set trap skill might be, and the base disarm DC is 20 plus your set trap level. In your case, it appears your set trap skill is 30.
This is why when Jiao was trying to examine, disarm, and recover, the respective DC for each action was 43, 50, and 60. Examine is the base DC (20) plus your skill level minus 7, the disarm DC is base plus skill level, and the recover DC is base plus skill level plus 10.
So, all those numbers appear to be okay. It should be noted that a person with a set trap skill level of 15 (the lowest possible to safely set this trap with a take20), would end up with DCs of 28, 35, and 45.
I can't compare your magic trap to any of the default traps in the game, since there are no magical traps in the system by default. However, it may be that when the builder established the trap template, he or she started with a spike trap and modified it. That may be why the system is registering it as a "spike trap" in the dialog box. However, as long as the DC's are correct, and the effects of an activated trap are correct, the fact that the system recognizes the trap as a "spike trap" is just a quirk, rather than a bug.
Nevertheless, I would tend to agree that the traps themselves should not weigh more than a default trap you can buy in-game. Also, the DCs do not seem to correlate well with the powers of the trap. In your example, the set trap DC is 35, which equates to a "deadly" trap DC in some of the standard default traps (some deadly traps are only DC 30). The disarm DCs for most default deadly traps with a set trap DC of 35, however, are:
Acid blob - 31 plus set trap score
Electrical - 36 plus set trap score
Fire - 36 plus set trap score
Gas (average) - 31 plus set trap score
Spike - 36 plus set trap score
As you can see, the default traps are just as hard to set as your crafted trap but are much harder to disarm. There are no default traps in NWN that have a disarm DC as low as 20 (even the minor traps have a base disarm DC of 22 as the lowest). The save DC of 25 is comparable to other default deadly traps, however.
Also, even though your magical trap does a respectable 6d12 of damage (half damage with reflex save), and few creatures have magical damage resistance, this really pales in comparison with the equivalent default traps listed above:
Acid blob - 18d6 plus paralysis save
Electrical - 30d6
Fire - 25d6
Gas (average) - ability damage
Spike - 25d6
In short, the magical trap you have is just as hard to set as other deadly traps, and has a comparable save DC, but does potentially less damage, and is easier to detect and disarm, and is also heavier to carry. However, I should caution that these are only the defaults within NWN, and that the builders could have modified these default traps as well. Also, the builders may have thought that because fire, cold, and electrical resistance is more commonly available than magical resistance, the lower damage amounts are justifiable. I think you might want to do an actual experiment comparing apples-to-apples: for example, craft a series of spike traps of increasing power, and compare them head-to-head against the spike traps you purchase from various vendors, and see if there is a substantial difference. You could do the same with fire, electrical, frost, etc. I have not seen a trap table anywhere on the forums that describes the stats for the crafted traps or default traps here on PoTM, so I don't know of any easy way to compare them short of running an actual experiment.
I would tend to agree with you, however -- if I have the choice between crafting a trap or buying an a trap with an equivalent "set trap" DC and save DC, I would pick the choice that gave me (1) a trap that is more difficult to detect and disarm, (2) the trap that gives me more damage, and (3) the trap that weighs less (rogues typically can't carry a lot). All else being equal, I would also pick the option that is less expensive.
