Trying to think in a sciencecy way (sciencey???)

I don't see how a bolt-on is possible.....help me out here but my understanding of a bolt-on would mean simply extending BETonMACe without alterations...I don't beleive they could simply swap out Stroke for CHF, that would to my mind represent a pretty major change. 

To me a bolt-on is kind of like extra innings for a baseball game....and changing the definition of 3point MACE to me would be like saying 'okay we're going to play 3 more innings, but any runs scored during the first 9 innings by way of a sacrifice fly now don't count'.