diff --git a/blip-0052.md b/blip-0052.md
index 46f266b..8e4d983 100644
--- a/blip-0052.md
+++ b/blip-0052.md
@@ -241,7 +241,8 @@ Example `lsps2.get_info` result:
             "max_payment_size_msat": "1000000",
             "promise": "abcdefghijklmnopqrstuvwxyz"
         }
-    ]
+    ],
+    "ongoing_proportional": true,
 }
 ```
 The `opening_fee_params_menu` is an array of `opening_fee_params`
@@ -294,7 +295,7 @@ and MUST NOT have any additional fields:
   to the client, not including the forwarding fees of nodes along the way.
 * `promise` is an arbitrary LSP-generated string that proves to the LSP that
   it has promised a specific `opening_fee_params` with the specific
-  `min_fee_msat`, `proportional`, `valid_until`, `min_lifetime`,
+  `min_fee_msat`, `proportional`, `valid_until`, `min_lifetime`, 
   `max_client_to_self_delay`, `min_payment_size_msat`, and
   `max_payment_size_msat`.
 
@@ -534,6 +535,10 @@ fn compute_opening_fee(payment_size_msat: u64,
 > overflow-detecting multiplication routine is optimized away
 > and replaced with a simple overflow-flag check.
 
+The `ongoing_proportional` field is a boolean that indicates whether
+the LSP will charge the agreed upon proportional fee on subsequent 
+payments after the initial channel open.
+
 ### 2.  Request JIT Channel
 
 The client constructs a request body for a `lsps2.buy` request,
@@ -560,7 +565,8 @@ Example `lsps2.buy` request parameters:
         "max_payment_size_msat": "1000000",
         "promise": "abcdefghijklmnopqrstuvwxyz"
     },
-    "payment_size_msat": "42000"
+    "ongoing_proportional": true,
+    "payment_size_msat": "42000",
 }
 ```
 
@@ -573,6 +579,12 @@ prove that it previously promised the specified `opening_fee_params`.
 LSPs MUST check that the `opening_fee_params.valid_until` is not a
 past datetime.
 
+`ongoing_proportional` is the boolean acquired from the previous step.
+Clients MUST provide the same value from a result of a `lsps2.get_info`
+call.
+LSPs MUST check that the `ongoing_proportional` field matches the mode 
+of operation they intend to use.
+
 `payment_size_msat` is an *optional* amount denominated in millisatoshis
 that the client wants to receive [<LSPS0.msat>][]:
 
@@ -614,6 +626,8 @@ The following errors are specified for `lsps2.buy`:
   and the LSP hit an overflow error while calculating the
   `opening_fee`, **OR** the LSP has insufficient incoming liquidity
   from the public network to receive the `payment_size_msat`.
+* `invalid_ongoing_proportional` (204) - the `ongoing_proportional` field
+  did not match the expected value.
 * [LSPS0.client_rejected_error][] (1) - The LSP rejected the client.
 
 If there were no errors, the LSP then provides a normal
@@ -1029,6 +1043,33 @@ selected.
 LSPs MUST consider this alias not just for forwarded payments, but
 also for onion messages.
 
+#### Ongoing Proportional Fees
+
+If `ongoing_proportional` is true then for all payments forwarded through 
+the channel after the initial channel-opening payment, the LSP MUST charge
+an ongoing proportional fee as specified in the `proportional` field from 
+the `opening_fee_params` used to open the channel.
+
+The ongoing fee for each payment is computed as:
+
+    ongoing_fee = ((payment_amount_msat * proportional) + 999999) / 1000000
+
+Where `payment_amount_msat` is the amount being forwarded to the client,
+and `proportional` is the value from the `opening_fee_params`.
+
+* All numbers MUST be computed using the same overflow detection rules
+  specified in the "Computing The `opening_fee`" section.
+* The LSP MUST deduct this `ongoing_fee` from each forwarded payment.
+* The LSP MUST include an `extra_fee` TLV (type 65537) in the
+  `update_add_htlc` message for each payment that has ongoing fees
+  deducted, with the value set to the computed `ongoing_fee`.
+* The client MUST accept these fee deductions and validate that the
+  `extra_fee` matches the expected `ongoing_fee` calculation.
+
+This ongoing fee allows LSPs to distribute the cost of channel opening
+across the lifetime of the channel rather than charging the full amount
+upfront on the first payment.
+
 [<LSPS0.msat>]: ./blip-0050.md#link-lsps0msat
 [<LSPS0.ppm>]: ./blip-0050.md#link-lsps0ppm
 [<LSPS0.datetime>]: ./blip-0050.md#link-lsps0datetime