The %% only applies to multiplayer games. So if you play solo you may well follow your friend's invitation without fearing a %% drop.
3128738: I repeat ' why do we need these percentages at all?
Try to look up the word "quitter" in this forum - myards of threads. These ppl who drop out of a multiplayer game voluntarily for various reasons are a pain for their company, interrupting their games, spoiling their fun. Reasons for quitting may be anger about a bad game or shot, anger about good play of the company, interruption by more important things like chefs and spouses, or plain cheating, looking to avoid credit losses in challenge matches.
The %% was created to make such behaviour visible. Those who inadvertedly lose connection to a game should be much less affected than repeat and voluntary quitters.
In theory, a good concept.
Alas, the %% count applies to ev1 not completing a MP game regardless of the reason. Thus, unfortunately not only the quitters and disconnectors are affected but also their victims, turning a good thing to bad because the number of innocents per definitionem exceeds the number of "culprits". In addition, some games' programming is weak against disconnections, causing unnecessary %% drops by design. These include Blitz and Skin games, and also strokeplay, since the introduction of the game lobby.
There may have been improvements but we haven't been told yet. Some news have been announced for next week's chat - who knows what they will say.