the docs were wrong

src/neonucleus.h

@@ -908,10 +908,10 @@ nn_Exit nn_dumptable(nn_Computer *computer, size_t idx, size_t *len);
 // computes the cost of the top [values] values using the same algorithm as
 // the modem.
 // It will return -1 if the values are invalid.
-// The algorithm is as mentioned in https://ocdoc.cil.li/component:modem
+// The algorithm is as mentioned in https://ocdoc.cil.li/component:modem, with 1 small change to match OC's code.
 // and is as follows:
 // - Every value adds a 2 byte overhead
-// - Numbers add another 8 bytes, true/false/null another 4 bytes, strings as
+// - Numbers add another 8 bytes, true/false/null another 1 byte, strings as
 // many bytes as they contain, except empty strings count as 1 byte.
 int nn_countValueCost(nn_Computer *computer, size_t values);