I regret your sleeplessness and confusion.  Please understand that the example is rendered in that fashion for illustrative purposes.   Namely, the user is meant to understand that five factors (Capacity, Equalization Rate, etc..) need to be considered.  In addition that there are two distinct processes (Rebuild and Equalization) involved in a rebuild.  With regard to units, it is the standard throughout Best Practicesis to show rates in MB/sec and storage capacities in GB.  Time is typically shown in seconds.  However, this example has an unusually long duration, and a conversion to hours seemed appropriate.  The unit conversions are included because they are many times forgotten in error.  The numeric example includes the likely manipulation of the data, to shorten the calculation.  Broadly the the equation includes in order:  rebuild duration, equalization duration, conversion to hours, and drive type and speed adjustment.  The following resulted from copying out the example into a MS Excel worksheet, deleting the unit designations, and clicking to let the Formula Wizard correct the parens:  =((400*(1/66))+(400*((1/82)))*(1024*(1/3600)))*1.33  The above result is 9.90603.  In the next revision of Best Practices, the same use of parens as shown above will be used.  I admit the example is a bit pedantic.  However many users do not have your through grasp of storage system 'speeds and feeds'.  They find the long form of the example helpful.  If you would like to suggest a better example, or have other comments, please submit a correction to the document through Powerlink.  This is the most reliable way for users to ask questions, have their concerns quickly addressed, and track document errors ensuring their correction.  Within the Powerlink search results window adjacent to the document title concerned is a link labeled Send Feedback to Author.  Click it, and you will get a Content Feedback window.   Fill it out. This will send your questions and comments directly to the author where they will be tracked.  The author will send you a response shortly.
This isn't really about calculating rebuild times as much as me just wondering if I am crazy/dumb or if there's a mistake in the FLARE 30 doc.   I'm pretty sure the example given on  page 91-92 for calculating rebuild times is not correct.  Two other things I noticed There were 8 open parenthesis '(' and 9 closed parenthesis ')'.  Not very good when doing math. Also, the example shows multiplying GB by MB (like units are always a must)  I dare someone to use this example and get the output that the doc says, even after converting all units to GB or MB (converting before you do any of the math in the equation).  Here's the example listed on page 91-92.   9.9 Hrs = ( ( 400 GB * (1/66.0) MB/s ) + ( 400 GB * ( (1/82.0) MB/s)) * (1024 MB/GB * (1/3600) sec/Hrs )) * 1.33 ).  This all started when I was seeing if any changes were made in rebuild/equalize times with FLARE 30.  I also was working on a nice little spreadsheet to calculate rebuild times for me.  I decided to plug in the example to make sure I was correct.  Now I can't sleep at night.       The formula listed in the doc also has more closed parenthesis than open ones.  It drives me bonkers!   As listed in the doc: Time = ((Failed hard drive capacity * Rebuild rate) * Drive type and speed adjustment) + ((Failed hard drive capacity * Equalization rate) * Drive type and speed adjustment))     
Rebuild times and FLARE 30 Best Practices example