Billy T,
"It is important to note that all the periods [Earth's orbit and year] were likely of different duration in the geological past." -- Mazmunder and Arima, 2004
Of course, OIM is lying here (lying in that he's misrepresenting what's actually said).
First off, in no way is it stated or implied in this section that Mazumder considers the earths orbit to have changed - which is what OIM has explicitly stated that he considers Mazumder to be saying.
What OIM is apparently incapable of doing is considering the scenario of tidal braking, where the Earths rotation slows by a few miliseconds every day (because the NAgular momentum is transfered to the moon).
Therefore, regarding only tidal braking, and the fact that 620 million years ago, the days would have been minutes shorter, one can accurately say that the period of the earth about the sun has changed, as well say that the period of the moon about the earth has changed.
The othe rthing that OIM is apparently ignorant of is that, as I have stated, Tidal rythimites can preserve Daily, monthly, and annual signals, thus giving us a direct measure of how many days are in the year.
This is different from considering that the orbit of the earth has (or hasn't) changed, and using that to calculate how many seconds long each day is.
"This implies that slow Earth expansion might have occured if G varies (Runcorn 1964, pg. 825)." -- Mazmunder and Arima, 2004
Here OIM is simply reiterating what i've already aknowledged was suggested by Keith Runcorn.