Hey,
well my idea is quite simple - add the count of the free Chapter on top of the one u have to pay for.
So u can see when a free chapter is released... otherwise it always shows u "hey we have a new chapter" then u click it and nothing changed because the new chapter only means a new one to pay... (so u get excited for nothing - and at least for me shows that the side really wants to suck my money out - same thing as reducing the bonus spirit points on purchases some time ago)
for me it doesn't matter if they add the one with add / 4 Spirit Stones to the "free" but well...