diff --git a/API/ROLAC.API.Tests/Services/MealAttendanceServiceTests.cs b/API/ROLAC.API.Tests/Services/MealAttendanceServiceTests.cs
new file mode 100644
index 0000000..69ce275
--- /dev/null
+++ b/API/ROLAC.API.Tests/Services/MealAttendanceServiceTests.cs
@@ -0,0 +1,60 @@
+using System.Security.Claims;
+using Microsoft.AspNetCore.Http;
+using Microsoft.EntityFrameworkCore;
+using Moq;
+using ROLAC.API.Data;
+using ROLAC.API.Data.Interceptors;
+using ROLAC.API.Services;
+using Xunit;
+
+namespace ROLAC.API.Tests.Services;
+
+public class MealAttendanceServiceTests
+{
+    // MealAttendance is auditable, so the InMemory provider requires CreatedBy/UpdatedBy
+    // to be set before insert. Wire in the AuditSaveChangesInterceptor (as the other
+    // service tests do) so those columns are stamped automatically on SaveChanges.
+    private static AppDbContext BuildDb()
+    {
+        var claims = new[] { new Claim(ClaimTypes.NameIdentifier, "test-user") };
+        var ctx    = new DefaultHttpContext { User = new(new ClaimsIdentity(claims)) };
+        var mock   = new Mock<IHttpContextAccessor>();
+        mock.Setup(x => x.HttpContext).Returns(ctx);
+        return new AppDbContext(new DbContextOptionsBuilder<AppDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .AddInterceptors(new AuditSaveChangesInterceptor(
+                new ROLAC.API.Services.Logging.CurrentUserAccessor(mock.Object))).Options);
+    }
+
+    [Fact]
+    public async Task SetCountsAsync_CreatesRowWhenMissing_AndReturnsTotals()
+    {
+        using var db = BuildDb();
+        var svc = new MealAttendanceService(db);
+        var date = new DateOnly(2026, 5, 31);
+
+        var result = await svc.SetCountsAsync(date, adult: 40, youth: 12, kid: 8);
+
+        Assert.Equal("2026-05-31", result.Date);
+        Assert.Equal(40, result.Adult);
+        Assert.Equal(12, result.Youth);
+        Assert.Equal(8, result.Kid);
+        Assert.Single(db.MealAttendances.Where(a => a.AttendanceDate == date));
+    }
+
+    [Fact]
+    public async Task SetCountsAsync_OverwritesExistingRow_AndClampsNegativesToZero()
+    {
+        using var db = BuildDb();
+        var svc = new MealAttendanceService(db);
+        var date = new DateOnly(2026, 5, 31);
+        await svc.SetCountsAsync(date, 40, 12, 8);
+
+        var result = await svc.SetCountsAsync(date, adult: 50, youth: -3, kid: 0);
+
+        Assert.Equal(50, result.Adult);
+        Assert.Equal(0,  result.Youth);   // negative clamped to zero
+        Assert.Equal(0,  result.Kid);
+        Assert.Single(db.MealAttendances.Where(a => a.AttendanceDate == date)); // still one row
+    }
+}
diff --git a/API/ROLAC.API/Services/IMealAttendanceService.cs b/API/ROLAC.API/Services/IMealAttendanceService.cs
index 05c122f..ba62136 100644
--- a/API/ROLAC.API/Services/IMealAttendanceService.cs
+++ b/API/ROLAC.API/Services/IMealAttendanceService.cs
@@ -22,6 +22,13 @@ public interface IMealAttendanceService
     /// </summary>
     Task<AttendanceCountsDto> SetAsync(DateOnly date, string category, int value);
 
+    /// <summary>
+    /// Overwrites all three age-group columns for <paramref name="date"/> with absolute
+    /// values (each clamped at zero), creating the row if it does not exist, and returns
+    /// the resulting authoritative counts. Used by the back-office Sunday-attendance editor.
+    /// </summary>
+    Task<AttendanceCountsDto> SetCountsAsync(DateOnly date, int adult, int youth, int kid);
+
     /// <summary>Returns the daily counts within the inclusive date range, ordered by date (for the dashboard).</summary>
     Task<IReadOnlyList<AttendanceCountsDto>> GetRangeAsync(DateOnly from, DateOnly to);
 }
diff --git a/API/ROLAC.API/Services/MealAttendanceService.cs b/API/ROLAC.API/Services/MealAttendanceService.cs
index 3f82717..f986b31 100644
--- a/API/ROLAC.API/Services/MealAttendanceService.cs
+++ b/API/ROLAC.API/Services/MealAttendanceService.cs
@@ -82,6 +82,24 @@ public class MealAttendanceService : IMealAttendanceService
         return await ReadAsync(date);
     }
 
+    public async Task<AttendanceCountsDto> SetCountsAsync(DateOnly date, int adult, int youth, int kid)
+    {
+        var row = await _db.MealAttendances.FirstOrDefaultAsync(a => a.AttendanceDate == date);
+        if (row is null)
+        {
+            row = new MealAttendance { AttendanceDate = date };
+            _db.MealAttendances.Add(row);
+        }
+
+        // Counts can never be negative; clamp before writing.
+        row.AdultCount = adult < 0 ? 0 : adult;
+        row.YouthCount = youth < 0 ? 0 : youth;
+        row.KidCount   = kid   < 0 ? 0 : kid;
+
+        await _db.SaveChangesAsync();
+        return ToDto(row);
+    }
+
     public async Task<IReadOnlyList<AttendanceCountsDto>> GetRangeAsync(DateOnly from, DateOnly to)
     {
         var rows = await _db.MealAttendances.AsNoTracking()