Based on the provided data, we can observe that the coin in question has had an average auction closing price of 45.93 euros in previous auctions. Additionally, its current condition is 85 (ebc-).

Considering that the coin will be auctioned in the upcoming days with a starting price of 25 euros, we can estimate a maximum purchase price based on the historical average auction closing price and the current condition. Given that the condition is quite good (85), and considering that the average auction closing price has been 45.93 euros, we could consider a maximum purchase price around 50-55 euros.

It is important to note that the final auction price may vary depending on the demand at that specific moment, so it is advisable to monitor the auction's progress to adjust the offer accordingly.