Yes. Any period of 34 consecutive hours off-duty will restart the 60/70 hour calculation. From http://www.fmcsa.dot.gov/rules-regulations/truck/driver/hos/hos-faqs.asp#_Toc111021257
http://www.fmcsa.dot.gov/rules-regulations/administration/rulemakings/final/05-16498-HOS-Final-Rule-8-25-05.htm is the Hours of Service Final Rule. I do not see anything in there about time off other than rules measured in hours, not days. J6, J7 and J8 are all in terms of hours.
Do you have a more specific reference to the regulation you heard about? If not, well, I can't find it.
You can contact the FMCSA through http://www.fmcsa.dot.gov/about/contact/who-to-contact/contactus.htm and ask them directly. I have not been able to find such a rule.
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