diff --git a/crates/maybenot/src/framework.rs b/crates/maybenot/src/framework.rs
index acee552..b91c403 100644
--- a/crates/maybenot/src/framework.rs
+++ b/crates/maybenot/src/framework.rs
@@ -518,11 +518,10 @@ where
         // does the machine limit say no, if set?
         if machine.max_blocking_frac > 0.0 {
             // TODO: swap to m_block_dur.div_duration_f64()
-            let f: f64 = m_block_dur.as_micros() as f64
-                / self
-                    .current_time
-                    .saturating_duration_since(runtime.machine_start)
-                    .as_micros() as f64;
+            let f: f64 = m_block_dur.div_duration_f64(
+                self.current_time
+                    .saturating_duration_since(runtime.machine_start),
+            );
             if f >= machine.max_blocking_frac {
                 return false;
             }
@@ -531,11 +530,10 @@ where
         // does the framework say no?
         if self.max_blocking_frac > 0.0 {
             // TODO: swap to g_block_dur.div_duration_f64()
-            let f: f64 = g_block_dur.as_micros() as f64
-                / self
-                    .current_time
-                    .saturating_duration_since(self.framework_start)
-                    .as_micros() as f64;
+            let f: f64 = g_block_dur.div_duration_f64(
+                self.current_time
+                    .saturating_duration_since(self.framework_start),
+            );
             if f >= self.max_blocking_frac {
                 return false;
             }
diff --git a/crates/maybenot/src/time.rs b/crates/maybenot/src/time.rs
index 5b1ebc4..99dd579 100644
--- a/crates/maybenot/src/time.rs
+++ b/crates/maybenot/src/time.rs
@@ -20,11 +20,11 @@ pub trait Duration: Clone + Copy + AddAssign + PartialOrd {
     /// Creates a new duration from the specified number of microseconds.
     fn from_micros(micros: u64) -> Self;
 
-    /// Returns the total number of whole microseconds contained by this duration.
-    fn as_micros(&self) -> u64;
-
     /// Returns true if this duration spans no time.
     fn is_zero(&self) -> bool;
+
+    /// Divide this duration by another Duration and return f64.
+    fn div_duration_f64(self, rhs: Self) -> f64;
 }
 
 impl Instant for std::time::Instant {
@@ -48,12 +48,14 @@ impl Duration for std::time::Duration {
     }
 
     #[inline(always)]
-    fn as_micros(&self) -> u64 {
-        self.as_micros() as u64
+    fn is_zero(&self) -> bool {
+        self.is_zero()
     }
 
     #[inline(always)]
-    fn is_zero(&self) -> bool {
-        self.is_zero()
+    fn div_duration_f64(self, rhs: Self) -> f64 {
+        // TODO: Can be changed to just `self.div_duration_f64(rhs)` when Rust 1.80 has
+        // been released and we are fine with that being the oldest working Rust version.
+        self.as_secs_f64() / rhs.as_secs_f64()
     }
 }