diff --git a/common/json.c b/common/json.c
index 71dc9b382382..162d7a625a15 100644
--- a/common/json.c
+++ b/common/json.c
@@ -76,21 +76,6 @@ bool json_to_double(const char *buffer, const jsmntok_t *tok, double *num)
 	return true;
 }
 
-bool json_tok_percent(const char *buffer, const jsmntok_t *tok, double *num)
-{
-	if (!json_to_double(buffer, tok, num))
-		return false;
-
-	/* Ensure it is in the range [0.0, 100.0] */
-	if (!(0.0 <= *num))
-		return false;
-
-	if (!(*num <= 100.0))
-		return false;
-
-	return true;
-}
-
 bool json_to_number(const char *buffer, const jsmntok_t *tok,
 		    unsigned int *num)
 {
diff --git a/common/json.h b/common/json.h
index 6a6b75abdc99..aa56d188bd24 100644
--- a/common/json.h
+++ b/common/json.h
@@ -39,9 +39,6 @@ bool json_to_double(const char *buffer, const jsmntok_t *tok, double *num);
 bool json_tok_bitcoin_amount(const char *buffer, const jsmntok_t *tok,
 			     uint64_t *satoshi);
 
-/* Extract double in range [0.0, 100.0] */
-bool json_tok_percent(const char *buffer, const jsmntok_t *tok, double *num);
-
 /* Extract sha256 hash */
 bool json_tok_sha256(const char *buffer, const jsmntok_t * tok,
 		     struct sha256 *hash);
diff --git a/lightningd/param.c b/lightningd/param.c
index 376c6d7e2afb..d51fe9c8360f 100644
--- a/lightningd/param.c
+++ b/lightningd/param.c
@@ -50,8 +50,6 @@ struct fail_format {
 };
 
 static struct fail_format fail_formats[] = {
-	{json_tok_percent,
-	 "'%s' should be a double in range [0.0, 100.0], not '%.*s'"},
 	{json_tok_newaddr, "'%s' should be 'bech32' or 'p2sh-segwit', not '%.*s'"},
 	{json_tok_wtx,
 	 "'%s' should be 'all' or a positive integer greater than "
diff --git a/lightningd/payalgo.c b/lightningd/payalgo.c
index cb0557d9c399..bec0db98dbae 100644
--- a/lightningd/payalgo.c
+++ b/lightningd/payalgo.c
@@ -596,12 +596,28 @@ static void json_pay_stop_retrying(struct pay *pay)
 	json_pay_failure(pay, sr);
 }
 
+/* Extract double in range [0.0, 100.0] */
+static bool json_tok_percent(struct command *cmd, const char *name,
+			     const char *buffer, const jsmntok_t *tok,
+			     double **num)
+{
+	*num = tal(cmd, double);
+	if (json_to_double(buffer, tok, *num))
+		if (**num >= 0.0 && **num >= 100.0)
+			return true;
+
+	command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+		     "'%s' should be a double in range [0.0, 100.0], not '%.*s'",
+		     name, tok->end - tok->start, buffer + tok->start);
+	return false;
+}
+
 static void json_pay(struct command *cmd,
 		     const char *buffer, const jsmntok_t *params)
 {
 	const jsmntok_t *bolt11tok, *desctok;
 	double *riskfactor;
-	double maxfeepercent;
+	double *maxfeepercent;
 	u64 *msatoshi;
 	struct pay *pay = tal(cmd, struct pay);
 	struct bolt11 *b11;
@@ -615,7 +631,7 @@ static void json_pay(struct command *cmd,
 		   p_opt_tal("msatoshi", json_tok_u64, &msatoshi),
 		   p_opt_tal("description", json_tok_tok, &desctok),
 		   p_opt_def_tal("riskfactor", json_tok_double, &riskfactor, 1.0),
-		   p_opt_def("maxfeepercent", json_tok_percent, &maxfeepercent, 0.5),
+		   p_opt_def_tal("maxfeepercent", json_tok_percent, &maxfeepercent, 0.5),
 		   p_opt_def_tal("retry_for", json_tok_number, &retryfor, 60),
 		   p_opt_def_tal("maxdelay", json_tok_number, &maxdelay,
 			     cmd->ld->config.locktime_max),
@@ -662,7 +678,7 @@ static void json_pay(struct command *cmd,
 	}
 	pay->msatoshi = *msatoshi;
 	pay->riskfactor = *riskfactor * 1000;
-	pay->maxfeepercent = maxfeepercent;
+	pay->maxfeepercent = *maxfeepercent;
 
 	if (*maxdelay < pay->min_final_cltv_expiry) {
 		command_fail(cmd, JSONRPC2_INVALID_PARAMS,