The various values for resistance are really valid for the week they were posted/edited and thats that - SD have changed beds at least 4 times through the life of the SD3. Who knows - the week they shipped yours they might have been using the same designed pad as SD2's... or even SD2 pads on the SD3.....
You may "not want to" contact support - but its best to speak to the people who collected your money as the information anyone else provides about what Solidoodle are shipping this week or last week or last month or last year are highly likely to be inaccurate - everyone here is really just at best guessing about what Solidoodle sent customers at whatever particular point in time it is as they do not communicate to us when they change things.
At the very least, Support will be able to, based on your Serial #, tell you what it shipped with and one would expect what its resistance should be.
They may then work through with you to check the heat-pad isn't damaged. Higher resistance can indicate shorts or something, or even just loose/poor connections - but in general a situation like that would raise your resistance considerably more than 0.4 .