mo nits

draft-ietf-quic-recovery.md

@@ -515,17 +515,15 @@ progress.
 
 ## Tracking Sent Packets {#tracking-sent-packets}
 
-Retransmittable packets MUST be tracked until acknowledged or lost in order to
-correctly implement congestion control. It is expected implementations will
-index this information by packet number and crypto context and store the
-per-packet fields ({{sent-packet-fields}}) for loss recovery and congestion
-control.
+To correctly implement congestion control, a QUIC sender tracks every
+retransmittable packet that it sends until the packet is acknowledged or lost.
+It is expected that implementations will be able to access this information by
+packet number and crypto context and store the per-packet fields
+({{sent-packet-fields}}) for loss recovery and congestion control.
 
 After a packet is declared lost, it SHOULD be tracked for an amount of time
 comparable to the maximum expected packet reordering, such as 1 RTT.  This
-allows detection of spurious retransmissions and MAY avoid extra
-retransmissions if the frames contained within the packet were
-retransmitted and lost again.
+allows for detection of spurious retransmissions.
 
 Sent packets are tracked for each packet number space, and ACK
 processing only applies to a single space.