As explained to me by Gunthar himself on Telegram, BOUGHT_PRICE is ONLY used for when you acquire coins through other means (ex: mining). In these situations, bot does not have any basis for calculations so you must override.
On coins that already have order book history, BOUGHT_PRICE does not do any overriding. Instead, it adds to and becomes part of the average bought price of all previous exchange history.
This Feature Request is for a per-pair parameter that either A) ignores all previous order history or B) sets a rate that supersedes all other orders.
Example: I have 100 trade history on BTC_LTC on Polo. Right now, LTC balance is 0. I transfer in some coins that I bought on another exchange for USDT. The bot should ignore all previous trade history on Polo and use my override'd BOUGHT_PRICE for all calculations.
Example implementation, ignore history older than X days when averaging bought price. This could also be set to the string "ALL" to ignore all order history. Setting to "ALL" would require a BOUGHT_PRICE to be set.
"BTC_LTC": { ..., "override": { "IGNORE_HISTORY": X } }