Hi Grace:
Based on what you say you're doing, I'm surprised you're getting 50% in this category. You suggest perception is at thye root. Here's a suggestion.
Next time you have new students, ask them on the very first day "how many would feel it would be fair if I graded and gave your quiz and test results back the same day?". I'm going to guess you'd get nearly 100% affirmative response. If some disagreed, ask them what more you could do. If it seems reasonable, you could consider it. But even if not, you have now set the expectation… >>>