Interesting. In terms of natural language, perhaps it simply doesn't understand where "sheet" fits in regards to technical specs. I put a couple combinations through the external adwords tool to see what happened:
technical specifications sheet
Unfortunately, Google thinks these are different things; a collided theme issue perhaps. Aside from taking out the "sheet" keyword, or maybe adding some specific anchor text for that phrase in conjunction with adding some synonyms of the sheet keyword, I see little that can be done by the webmaster. Training the filters to grow themes appropriately seems like a whole different topic.