unsigned bit fields overflow

Suppose we have a continuous process where we increment an unsigned char +1 or -1 and we want it to always stay in a range between 0 , 2^n - 1,lets say for example that this range is 0 , 15, I know that it is possible to do something like this:

unsigned char offset = 0;

while( condition )
{
    if(something)
    {
       offset += 1;
    }else
    {
       offset -= 1;
    }
    offset %= 16;
}

I wanted to know if it is possible to the same thing with bit fields, and whether it had any benefits:

unsigned char offset : 4;
offset = 0;

while( condition )
{
    if(something)
    {
       offset += 1;
    }else
    {
       offset -= 1;
    }
}

I am asking because if I understand it correctly, the first version will perform the % at every loop iteration, while the second will only do it ( if what I read is correct) when offset tries to overflow.