<I'm trying to find out how long it should take for such a positive
<breath reading to remian in the blood system?

The units here are grams % (g/dl) Breath is usually reported in grams
per 200 liters of air so I think the units you are using are BAC
equivalents and not liters of air. It would be 62mg/dl equal to 0.062g%

You would start out at 0.062 and after one hour it would be - 0.017 or
0.045 g%, 0.028, 0.011 and after four hours 0.

"Although the average metabolism rate for moderate drinkers produces a
.017 per hour decline in BAC level (here termed "Average"), and the
average metabolism rate for heavy drinkers (who consume 60 drinks or
more in one month) produces a .02 per hour decline (here termed "Above
Average"), the range of metabolism rate in the population can go above
.040 and below .010. One can either utilize in the calculation the
average (.017 per hour decline) metabolism rate, or if one wished to
use a very conservative figure, (which less than 20 percent of the
population would exhibit), one could use .012 per hour decline (here
termed "Below Average") [Note: the BAC Estimator program provides BAC
estimates for above average, average, and below average metabolism
rates automatically. These three categories of metabolism rate closely
approximate a drinker's recent drinking pattern, i.e., frequency and
quantity of consumption.]

H. In real life, time must pass for the consumption, absorption, and
distribution of alcohol throughout the body. Therefore, we calculate
what the actual BAC level would be at the end of one hour after
consuming the single can of beer. During this period, the body would
have disposed of alcohol through metabolism at a rate characteristic of
that individual, primarily his recent frequency and quantity of
drinking. Utilizing a conservative (below average) metabolism rate of
.012 per hour, we can calculate the BAC level as .0302 - .012 per hour
X 1 hour = .0182 BAC at the end of one hour for our 128 lb. male who
drank 1 can of beer. (As noted above, the BAC Estimator program
rounds-off BAC estimates to two decimal places, thus it would report a
calculated BAC of .0182 as .02.) Note that the time of metabolism is
calculated from the beginning of drinking, not when the consumption is
completed."

http://www.nhtsa.dot.gov/people/injury/alcohol/bacreport.html

Conversion factors and problems here in

http://www.forensic-evidence.com/site/Biol_Evid/Breath_Tests.html

"The conversion factor Q, obtained by division of blood alcohol
concentration (BAC) by breath alcohol concentration (BrAC) is a widely
discussed topic due to its great variance. By Austrian law, regulations
frequently require an estimation of a corresponding BAC by a measured
BrAC. It is known that Q depends among other things, on the alcohol
kinetic state of the person being tested, which mathematically can be
transformed to a dependency on the BrAC. Theoretically calculated Q
values per BrAC level form a hyperbola shaped curve, thus decreasing
with increasing BrAC values. Applying Austrian forensic standards for
BAC and BrAC measurements, these calculations were verified in a study
under practical conditions with BAC and BrAC data of 390 individuals. Q
decreases from 2629 (+/- 455) for BrAC levels < 0.1 mg/l to 2229 (+/-
160) for a BrAC range of 0.4-0.5 mg/l and increases again to 2428 (+/-
124) for BrAC levels > 0.6 mg/l. Since these results were obtained
under realistic practical conditions they can be directly applied in
routine forensic expert opinion and can eliminate avoidable variances
in the calculation of Q.

PMID: 15993021 [PubMed - in process]

Here is some info on the breathalyzer and things that can go wrong.

http://nydwi.com/Articles/index.php?Cross%20Examining%20a%20BTO

Enjoy