"If you have placed your bid with EuroBonus points, you will not earn EuroBonus points if your upgrade is successful"
Does that mean that you won't even get EB points for your original class? If so, then you have to add those lost points to your bid to get the real price of your bid.
Even if they still give EB points for your original class that's still a big percentage increase in points. For example, I've upgraded recently to the Canaries from CPH for 5,000 points, but I got 1,000 back in extra EB points earned in Plus which reduced the net bid to a 4,000 points. Now it's 25% more expensive to bid for an upgrade on that route.