NPR Story on the Ikea Effect talks about this paper.

Our account suggests that labor leads to increased valuation only when labor results in successful completion of tasks; thus when participants built and then destroyed their creations, or failed to complete them, the IKEA effect dissipated.

The logic is the love is due to the labor, sense of accomplishment. From there,

Mochon's experiments actually have serious big-picture implications. The world over, companies and managers fall in love with their own ideas — and reject better ideas from the outside because they were not designed in-house.

Is it true for everything you do ? Does your expertise in the task count ? Personally, I have different bars for assembling furniture vs the work I do.