On a Mobile device, use Summary Dto or Aggregate over details?

I am building a Mobile App that manages Time Entry. I have 3 screens, Weekly Summary (WS), Daily Summary (DS) and Daily Time Entries (TE). WS & DS are presented in lists and DE is a typical detail page. Navigation flows, WS->DS->DE. My concern is performance. I can retrieve all Time Entries and summarize client-side for Weekly Summaries, or I can use Summary Dtos and retrieve the TE only when requested as we navigate to the TE (detail) view. There's probably 6 entries per day and that rolls up to a current week in the summary. It seems wasteful to load all Time Entries for the week because the user may never navigate to that day or need to edit one of those records. Any advice for the best path forward. Thanks in advance.