Wallbilly, I wouldn't get concerned about losing a few reps here or there. That's just the nature of lifting, and so many life-things can affect your performance from session to session. The beauty of TB is that the hi-frequency approach tends to auto-correct that over time. You're not as reliant on...

Nice find....so do both and the heart gets hit from every angle.

Apex has really taken my conditioning game to the next level. Can't say it's my favorite, but probably the most effective. Far as faves go, I really enjoy 600M resets and nasty nasty Fobbitses (said in my best Smeagol voice).