The 16,000 shown above your Level indicator is your accumulated red chips total. The event screen shows you the additional number of chips required to unlock the item, disregarding the previous item's cost.
Therefore, 6,800 of your 16,000-ish went to unlocking Burn's Fountain, the remaining (16,000 - 6,800) contribute towards the next 15,900 chips required for the Wedding Chapel.
i.e. by the time you unlock the Chapel, you would have accumulated 22,700 chips (6,800 + 15,900).
so on...