The Learner's dictionary [http://learnersdictionary.com/definition/should] (written for English learners) puts it this way: somewhat formal — used to talk about the result or effect of something that may happen or be true Should [=if] you change your mind, please let us know. I will feel very guilty should anything go wrong. [=if anything goes wrong] — usually used with if I will feel very guilty if anything should [=were to] go wrong. If he should call [=if he calls], tell him I'm not home. If you should see them [=if you see them], say hello for me.

Thank you!! :)))

I think, senteces that start with "If" are all correct. While the sentences that start with "Should" are incorrect.

Firstly, it would be either "should you have any problemS" or "should you have a problem". There is really no difference between should and if in these contexts. Should sounds more formal and old fashioned if anything. Furthermore you can combine them: "If you should have any problems please..." for maximum formality. "Should I finish my work in august I will get a great bonus" sounds slightly awkward. It's correct grammatically but sounds as if someone is trying too hard to speak like Jacob Rees-Mogg.