Others can weigh in by emailing me additions to my comments.
Your students will know their final grade by checking their portals. At this time, if anyone objects to their grade and lets you know, you can do your own review, and take it from there. Inform the student, and if necessary, get a change of grade form that will be co-signed by the Chair and the Dean, and it is fixed. We all make mistakes. Personally, I have had errors and they almost always happen when I have many, many students and I think it's a good time to migrate to a new system mid-semester. Bad idea--my advice would be to use a system you like and keep it. Some students are particular about BlackBoard Learn, and check it for grades. They may complain if you do not. Many instructors love it as well. But not all.
Strange things can happen with student records and piles of assignments. Keep your records, as you know it is required for the very purpose of cross-referencing. Some instructors let students know before the final input what their grades will be, and delay the process until all students have had a reasonable time to respond. Remember it is the student's responsibility to be aware of their own progress. By all means help as much as you are willing and able, but their performance is their responsibility. This is a key point, because some instructors, tenured or not, experienced or not, may feel sympathy when a distressed student appears because they are trying to graduate and somehow missed the fact that they failed your class(es). Or they forgot to tell you earlier, but they really must have am A and not a B+ because (fill urgent life-altering reason in the blank). They wonder what you can do.
Sympathy transformed to a firm epathetic position is powerful. Yes, life feels unfair. Growing up is hard. We are each responsibile for our actions, and one of them is to check our progress against the standards we have set for our own personal and professional development. Our future employers would expect no less.