diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index b165b318a..2bf9fbecd 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -138,7 +138,7 @@ Monty Evans <montyevans@gmail.com>
 Nil Admirari <https://github.com/nihil-admirari>
 Michael Winkworth <github.com/SteelColossus>
 Mateusz Wojewoda <kawa1.11@o2.pl>
-Jarrett Ye <jarrett.ye@outlook.com>
+Jarrett Ye <jarrett.ye@outlook.com> 
 Sam Waechter <github.com/swektr>
 Michael Eliachevitch <m.eliachevitch@posteo.de>
 
diff --git a/rslib/src/scheduler/fsrs/retention.rs b/rslib/src/scheduler/fsrs/retention.rs
index 64dfd5987..d8dd43ab0 100644
--- a/rslib/src/scheduler/fsrs/retention.rs
+++ b/rslib/src/scheduler/fsrs/retention.rs
@@ -76,12 +76,15 @@ impl Collection {
 
         let first_rating_count = revlogs
             .iter()
-            .filter(|r| {
-                r.review_kind == RevlogReviewKind::Learning
-                    && r.last_interval == 0
-                    && r.button_chosen >= 1
+            .group_by(|r| r.cid)
+            .into_iter()
+            .map(|(_cid, group)| {
+                group
+                    .into_iter()
+                    .find(|r| r.review_kind == RevlogReviewKind::Learning && r.button_chosen >= 1)
             })
-            .counts_by(|r| r.button_chosen);
+            .filter(|r| r.is_some())
+            .counts_by(|r| r.unwrap().button_chosen);
         let total_first = first_rating_count.values().sum::<usize>() as f64;
         let first_rating_prob = if total_first > 0.0 {
             let mut arr = [0.0; 4];
@@ -136,11 +139,10 @@ impl Collection {
         let learn_cost = {
             let revlogs_filter = revlogs
                 .iter()
-                .filter(|r| r.review_kind == RevlogReviewKind::Learning && r.last_interval == 0)
+                .filter(|r| r.review_kind == RevlogReviewKind::Learning && r.button_chosen >= 1)
                 .map(|r| r.taken_millis);
-            let count = revlogs_filter.clone().count() as f64;
-            if count > 0.0 {
-                revlogs_filter.sum::<u32>() as f64 / count / 1000.0
+            if total_first > 0.0 {
+                revlogs_filter.sum::<u32>() as f64 / total_first / 1000.0
             } else {
                 return Err(AnkiError::FsrsInsufficientData);
             }