Different formula used for newer HB humidity sensor????

Hi,
Recently I had to replace my HB Temp/Hum/Solar board due to corrosion. It was around 3-4 yeaqrs old.
The replacement board has the newer humidity sensor chip with the fine gauze over the sensor hole in the chip. The old sensor would report 99% and sometimes 100% hum when conditions justified that ie saturated air with mist blowing past the weather station and everything dripping with water/condensation. The new sensor never reports above 94% and struggles to reach that under the same very humid conditions described above.
I wrote to Eric at HB and asked for his comments. He replied that he was aware that the new sensor used a slightly different formula to calculate humidity but did not know if that would explain what I was seeing.
So my questions are:-

Has any other 1-wire user seen this?
Is Brian aware of the formula change and if this formula change could explain what I am seeing?
w0mbat

I am not aware of any formula change (i.e what the change is to)

It was my mis-remembering. I just looked up the formula for both the old HIH-3600 and and newer HIH-4021 and they are the same. I could have sworn that the newer sensor had a slightly different formula.

Eric