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No. OP and Crescent posted about collections that have items dropping from different sources, sources that have vastly different rate of occurring, so the collection is to be expected to not build up evenly. It can be balanced pretty easily, by selecting guest planes or wasting clicks on Sport Shops.

You brought a collection with all items from one source, with supposedly same drop rates, so the imbalance is actually unexpected and can't be explained by simply reading description. An entirely different issue.