Do you have limited elevator authority? Seems like it can’t go up much further. Could also be that the visible representation is wrong. MSFS does have weird visuals when it comes to trim, on the C172 for example you would only see the trimtab move in flight when trimming without really moving the elevator. This is partly because of limitations regarding joysticks without floating in-trim position. It should be possible to simulate a trimmable horizontal stabilizer correctly, although on the default Airbus this is also not 100% accurately simulated.