Servicing issue. My PITI monthly payment is $ XXXX/mo I routinely pay {$2500.00} or {$150.00} extra which I intend to be used towards princiipal. This is not applied ( I assume it would allow me to avaoid a little ineterst. Servicer is un willing to make this change except on a month by month basis- they want me to provide a letter each month that I over pay. Ditech For some reason this does not feel right 
