I don't know about difficulty level of 10th. I gave it on 11th. What i can say easily is that physics for 4th was a bit high, however the difference was for me like 5% change only. Maths was kinda similar in both the papers. HOWEVER chemistry, in 4th i took the same test, same day and i was easily able to score 80+ in it without any guesses and thats because in that paper the questions were actually good enough, they didn't had much cramming part as compared to the one on 11th which had two questions from salt analysis only and many other questions from inorganic too which required pure cramming. Yes there were 10 questions in inorganic on 4th however they didn't required the special "mugging" of data and could be solved mostly with normal properties.
Now in respect to your question, it is highly unlikely that CBSE is going to ever ever do something like that as Difficulty is relative. It would be unfair to offline students if online students are given more normalized score and vice versa.
Furthermore, what was surely wrong was there were many ambigious questions in JEE Paper to my knowledge on 4th april, so that means that all offline candidates would be getting +12 marks for free YES FREE! No matter if you worked on those questions, wasted time on it or not, you are gonna enjoy those marks.
However, nothing like that was found in online papers. And even if it is then thats a mistake from CBSE which a national board must have been more strictly checked before paper began. The consequences are 4 lakh online candidates are for sure going to lag by 12 marks by 8 lakh offline candidates by 12 marks for sure if they award full marks to offline candidates. This is just wrong and shouldn't have been done ANYWAY. CBSE needs to accept their fault on this thing, nothing much can be done about it now though except for CBSE accepting their irresponsibility.
And moreover Life is not always fair