1 Kings 7:23 and 2 Chronicles 4:2.
I have seen this before and I believe you are in error in its interpretation. The rim and the circumfurance of the vessel itself are not necessarily the same. For example, my tea cup might measure 3 inches around but while its rim measures 3.14 inches in diameter.
Seeing that the text descibes a rim and seeing that the vessel was designed to bath in a rim wider than the main vessel makes perfect sense.
1. Those "two verses" are the same verse reported in two different books. It's really only one verse.
2. As VRWC_minion has already told you, there is a significant difference between the inside and outside diameter.
3. Even if the ID and OD difference didn't exist, there is the simple matter of measurement, and what you claim is "two significant digits." The verse reports a measurement in cubits only. IOW, the measurement is recorded to the nearest cubit, not to the second significant digit. If we assume that the circumference figure is accurate, the diameter figure (9.55) is rounded to the next higher cubit.
Even eighth graders used to be taught the rules for recording measurements and for rounding. It doesn't take a Physicist to figure these things out.
Your agenda appears to be leading your science around by the nose.