I think your being a little hard on yourself. If some questions take longer, some questions may not take as long and as long as it balances you're fine. These targets are just that, not some hard rule. For instance some games I can finish them in a quarter of the time allotted, but for others I take more time than recommended. To improve though, you just need to keep practicing and the patterns/ answers will come to you. Figuring out the general direction of the answer before you even read the question stem will eventually come to you too.