I find 50 silvers too expensive to be able to remove just one second malus. It would be better if its price was 30 silvers. An average person spends 5 chances to win a challenge. That means 50 silvers. Eventhough, he did have 240 silvers at first place, his remaining silver count will be 190. If he wants to reduce 3 sec malus he will spend 150 of it. And, he will have 4 tryings and 6 second malus. I think it is little bit unfair. I know indiegala must make profit but; I don't know what to say.
50 galasilver is honestly fine, that's because the average user doesn't need to spend 5 chances to win a challenge (if you're talking about yourself, there are plenty of video posted about how to win more) and it would only benefit people who are winning a lot.
Let's take for example a new guy that has -8 seconds after every win because he joined the Indiegala group. Assuming he has read this forum in search of tips and saw how to play with videos, in a week or two he would win 3 games (one random game, either mining or archer, then hoeing using the malus removal), so that means he won't feel the difference between one reduction or the other. If he hasn't read the forums he probably won't win much anyway and spend the rest of silvers in giveaways.
The average user (he's been here for a lot more time) has only a -6 seconds reduction for every win and knows how to play, he still isn't that great at playing tho. Like some experienced new guy he can win 3 games per day, but on lucky days he can manage to win at -15 seconds at hoeing and win 4 games per day. With your reduction he would win 4 games more consistently, but not everytime.
Then talking about the more experienced users, they would abuse the system more and win either 1 or more games every day, the rich gets richer.
Also I don't think Indiegala makes profit this way, probably only gets more traffic and way too little to consider it profit. But old keys must go somewhere.