diff --git a/docs/Smart-Meter-Interface.md b/docs/Smart-Meter-Interface.md
index 2746c97fd7..8759d9b084 100644
--- a/docs/Smart-Meter-Interface.md
+++ b/docs/Smart-Meter-Interface.md
@@ -215,7 +215,7 @@ With `=` character at the beginning of a line you can do some special decoding.
 | `*` character | To hide fields from result output or disable output completely. Compiling with `USE_SML_SCRIPT_CMD` required. <BR> - as single character in `<label>` of the metrics line will hide that value from the web UI <BR> - as single character in `<label>` of the meter definition line will suppress the entire JSON output on MQTT |
 | `M,=so1 `| special SML option for meters that use a bit in the status register to sign import or export like ED300L, AS2020 or DTZ541 <BR>e.g. 1,=so1,00010800,65,11,65,11,00100700 for DTZ541<BR> 1. obis code that holds the direction bit, 2. Flag identifier, 3. direction bit, 4. second Flag identifier (some meters use 2 different flags), 5. second bit, 6 obis code of value to be inverted on direction bit.<BR>|
 | `M,=so2 `| if 1 fixes the bug introduced by meter DWS74, if 2 enabled OBIS line compare mode instead of shift compare mode, if 4 invert hardware serial line.<BR>e.g. 1,=so2,2 enable obis line compare.<BR>|
-| `M,=so3 `| sets serial buffer size, serial IRQ buffer size and serial dump buffer size.<BR>enter as a new descriptor line e.g. 1,=so3,512 sets serial buffer size to 512. (default buffer is 48 bytes input, 128 bytes dump)<BR>|
+| `M,=so3 `| sets serial buffer size, serial IRQ buffer size and serial dump buffer size.<BR>enter as a new descriptor line e.g. 1,=so3,512 sets serial buffer size to 512. (default buffer is 48 bytes input, 128 bytes dump)<BR>note: size should fit to the maximum length of a single line of decoding description; too big buffer sizes lead to delayed WebUI/MQTT updates|
 | `M,=so4 `| sets AES decrytion key for encrypted meters.must define exactly 16 hexadecimal chars<BR>e.g. 1,=so4,deabcd0020a0cfdedeabcd0020a0cfde sets decryption key and enables decrypt mode for that meter.<BR>|
 | `M,=so5 `| sets AES authentication key for encrypted meters.must define exactly 16 hexadecimal chars<BR>e.g. not needed by most energy meters (needs USE_SML_AUTHKEY).<BR>|
 | `M,=so6 `| sync time in milliseconds for serial block detection with AMS meters (defaults to 1000).<BR>|