Of course it is a misinterpretation of the text and I am so sick of people that try to use it as an example that the Bible is not the word of God - all they have to do is read the text and it's clear that the numbers 10 and 30 as given weren't exactly referring to the same things. Here's what I think is a description of what you've suggested as the correct interpretation.
http://www.answersingenesis.org/creation/v17/i2/pi.asp
Are you also familiar with the discussion that there is in fact a very accurate rendering of pi that can be derived from the account of the vessel when one uses both the Kings and Chronicles verses? In fact, it is accurate to the 4th decimal place for an accuracy which is within 0.00026% of the true value for pi.
http://answering-islam.org.uk/Religions/Numerics/pi.html