Theoretically, strings would flex perfectly and ideally and intonation adjustability would not be needed, but in real life, they behave quite differently. In practice, the stiffness of strings at the ends tend to make them act like they are shorter than the measured length of the string, and you adjust the bridge to compensate for that stiffness.
As strings get thicker, you usually expect the strings to get more stiff and require more intonation adjustment. But that's not guaranteed, because the stiffness is not only a function of gauge - the thickness of the core wire and wrap wires, construction, and materials all factor in too. So, you should expect intonation adjustments will be required any time you change brands or gauges of strings. Hopefully, if you replace your current strings with the same brand and gauge you *won't* have to reset the intonation!
Unfortunately, if the overall setup is appropriate, and the bridge doesn't have enough travel to bring it to proper intonation, you may not be able to use this particular string. I love Rotosound Swing Bass strings too, but don't use them on my 5-string basses because I never had good results on the low-B. This wasn't an intonation problem for me, but I found that the low B just sounds very different than the other 4 strings.
It may be worth trying a different B-string, but that may be an expensive experiment.
For what it's worth, I've had better luck with GHS Boomers and DR Low-Riders depending on the instrument, but don't like them as much as the Roto 4-string set.
David Fung
