It wasn't personal. You are asking an opinion from someone in MD/PhD ad com. Research is research whether is wet or dry. However, AdComms have a higher amount of suspicion when considerable hours haven't translated into poster, presentations, and manuscripts. Clearly, breaking thru coding or data brick walls is hard. If a project has taken much longer in being productive, the LORs must reflect that. In part, the requirement for research LOR from each substantial experience is to interpret those research hours. Best wishes... I apologize if you felt targeted.