Interaction between row editor and renderer in grid ?

I have a store that stores its values in bytes, I want the grid editor to display the column in MB.

So I added a renderer function to the column.

However when I enabled row editing the value that is saved to the store is MB (which the renderer function then processes into a very small number)

Is there a way to write the bytes value to the underlying store, while still preserving the MB value in the display ?

Code:

...       
}, {
            header: 'Minimum (MB/s)',
            sortable: true,
            dataIndex: 'minimum',
            xtype: 'numbercolumn',
            editor : {
                xtype: 'numberfield'
            },
            renderer : function ( value, metadata, record ) {


                var MBs = parseInt( value );


                return MBs / ( 1024 * 1024 );
        
            }
        }, {
...

Interaction between row editor and renderer in grid ?