That sounds about right. I just tell my kids the grade they are in based on age. So, my DD8 is going into 3rd grade and my DD10 is going into 5th grade.
As for the work that they do, my DD8 will be doing mostly 4th/5th grade work. A couple things might be more 3rd grade like copywork.
My DD10 is doing 4th/5th grade work but her reading is probably more like 3rd/4th grade.
We use the grade based by age so that when they are at library or VBS or church things that are divided by grade, then they are still in an age appropriate group. If there will be a lot of reading I have talked with the leader for my oldest and let them know privately that she struggles so that she isn’t put on the spot in front of all the other kids. For my youngest it doesn’t really matter.
On a funny note, when my youngest was “1st grade” she knew she was in first grade but suddenly one day started telling people she was in 2nd grade. When I asked her about it she said that it was a new year (January) and so she figured she was in a new grade. =)