How do you rectify min vs distance?

This question gets asked fairly frequently, and Mike Ricci, who wrote most of our plans, is the person to best answer it. This is from a previous post he made on the subject:

...plans are built on time, b/c your body knows time, not distance. That's how the human body works - pretty simply put. I have been coaching this way, very effectively I might add, over the last twenty years. You 'could' train by distance, but I don't think your improvement would be as quick as if you used a HRM and trained by TIME.

 Here's another :

The problem being that one hour could be 12 miles for one person, or 24 for another. This is the same situation for the swimming. If I put down swim 3000 yds in 50 minutes, most people will think I am nuts, while others will say its right on, so its a tough call and that's why I think we can give you a range, but not really a definite mileage. If there were a way in the plan to say 60 minute ride - 12-24 miles depending in ability, I think that would be a bonus.

The other factor is that if you can run 20 minutes in one of our plans, I can pretty much gaurantee you can run the 5k in the race. I do like creating plans by minutes so athletes aren't thinking "the plan called for 2.5 miles in 20 minutes, so I have to really push hard today" when in reality the run was supposed to be a Zone 2 20' run. 

OK, thanks for the replies....I guess the underlying question is....if I am basically slow at all three disciplines, but complete the times/minutes called for, will I be adequately prepared to go the distance?  Am I correct in taking your replies as "yes" I should be prepared to complete the distances?

(Please excuse my worrisome-self) 

(And I just relized that I put this post in the wrong category)

I know several people that tack onto the bike mileage the actual race distance for peak weeks...more of a mental 'I can do this distance'...though many have indicated that if they stuck with the plan minutes (even though they didn't do the full race distance) got them through fine.

With the swim, that's one thing I would make sure you can definitely do the yardage of your race - even 10% over...adjust the plan up if needed.

The run.  It depends on how 'short' you will be coming up to 13 miles...if it's a few miles, you should be fine, if it's more that that you may want to extend a few of your long runs to get you close to race distance...of course assuming you aren't jumping up in run volume...

Though I would err on the side of caution and do what JohnnyKay said in his post earlier.