diff --git a/docs/getting_started/installation_and_usage.md b/docs/getting_started/installation_and_usage.md
index 175bf545a..d1c4a079a 100644
--- a/docs/getting_started/installation_and_usage.md
+++ b/docs/getting_started/installation_and_usage.md
@@ -342,7 +342,7 @@ tools.build:compiler_executables={"c": "gcc-12", "cpp": "g++-12"}
 
 [`MP_UNITS_API_STD_FORMAT`](#MP_UNITS_API_STD_FORMAT){ #MP_UNITS_API_STD_FORMAT }
 
-:   [:octicons-tag-24: 2.2.0][use fmtlib support] · :octicons-milestone-24: `AUTO`/`ON`/`OFF` (Default: `AUTO`)
+:   [:octicons-tag-24: 2.2.0][use fmtlib support] · :octicons-milestone-24: `AUTO`/`TRUE`/`FALSE` (Default: `AUTO`)
 
     Enables the usage of [`std::format`](https://en.cppreference.com/w/cpp/utility/format/format)
     and associated facilities for text formatting. If it is not supported, then
@@ -352,7 +352,7 @@ tools.build:compiler_executables={"c": "gcc-12", "cpp": "g++-12"}
 
 [`MP_UNITS_API_STRING_VIEW_RET`](#MP_UNITS_API_STRING_VIEW_RET){ #MP_UNITS_API_STRING_VIEW_RET }
 
-:   [:octicons-tag-24: 2.2.0][cmake returning string_view] · :octicons-milestone-24: `AUTO`/`ON`/`OFF` (Default: `AUTO`)
+:   [:octicons-tag-24: 2.2.0][cmake returning string_view] · :octicons-milestone-24: `AUTO`/`TRUE`/`FALSE` (Default: `AUTO`)
 
     Enables returning `std::string_view` from the
     [`unit_symbol()`](../users_guide/framework_basics/text_output.md#unit_symbol)
@@ -364,7 +364,7 @@ tools.build:compiler_executables={"c": "gcc-12", "cpp": "g++-12"}
 
 [`MP_UNITS_API_NO_CRTP`](#MP_UNITS_API_NO_CRTP){ #MP_UNITS_API_NO_CRTP }
 
-:   [:octicons-tag-24: 2.2.0][cmake no crtp support] · :octicons-milestone-24: `AUTO`/`ON`/`OFF` (Default: `AUTO`)
+:   [:octicons-tag-24: 2.2.0][cmake no crtp support] · :octicons-milestone-24: `AUTO`/`TRUE`/`FALSE` (Default: `AUTO`)
 
     Removes the need for the usage of the CRTP idiom in the
     [`quantity_spec` definitions](../users_guide/framework_basics/systems_of_quantities.md#defining-quantities).
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index cee2b7f17..edbaac1ed 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -85,7 +85,7 @@ check_cxx_feature_supported(__cpp_explicit_this_parameter ${projectPrefix}EXPLIC
 
 # validate settings
 if(NOT ${projectPrefix}API_FREESTANDING
-   AND ${projectPrefix}API_STD_FORMAT STREQUAL "TRUE"
+   AND "${projectPrefix}API_STD_FORMAT"
    AND NOT
        (${projectPrefix}LIB_FORMAT_SUPPORTED
         # libc++ has a basic supports for std::format but does not set __cpp_lib_format
@@ -96,13 +96,11 @@ if(NOT ${projectPrefix}API_FREESTANDING
     message(FATAL_ERROR "`std::format` enabled but not supported")
 endif()
 
-if(${projectPrefix}API_STRING_VIEW_RET STREQUAL "TRUE" AND NOT
-                                                           ${projectPrefix}STATIC_CONSTEXPR_VARS_IN_CONSTEXPR_FUNCTIONS
-)
+if("${projectPrefix}API_STRING_VIEW_RET" AND NOT ${projectPrefix}STATIC_CONSTEXPR_VARS_IN_CONSTEXPR_FUNCTIONS)
     message(FATAL_ERROR "`std::string_view` returns enabled but not supported")
 endif()
 
-if(${projectPrefix}API_NO_CRTP STREQUAL "TRUE" AND NOT ${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED)
+if("${projectPrefix}API_NO_CRTP" AND NOT ${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED)
     message(FATAL_ERROR "`NO_CRTP` mode enabled but explicit `this` parameter is not supported")
 endif()
 
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 9d2839f30..45c91dd01 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -23,8 +23,7 @@
 cmake_minimum_required(VERSION 3.23)
 
 function(set_feature_flag name)
-    set(val_list "TRUE" "FALSE")
-    if(${projectPrefix}${name} IN_LIST val_list)
+    if(NOT ${projectPrefix}${name} STREQUAL "AUTO")
         target_compile_definitions(
             mp-units-core ${${projectPrefix}TARGET_SCOPE} ${projectPrefix}${name}=$<BOOL:${${projectPrefix}${name}}>
         )
@@ -99,8 +98,8 @@ set_feature_flag(API_NO_CRTP)
 
 # Text formatting
 if(NOT ${projectPrefix}API_FREESTANDING
-   AND (${projectPrefix}API_STD_FORMAT STREQUAL "FALSE" OR (${projectPrefix}API_STD_FORMAT STREQUAL "AUTO"
-                                                            AND NOT ${projectPrefix}LIB_FORMAT_SUPPORTED))
+   AND (NOT ${projectPrefix}API_STD_FORMAT OR (${projectPrefix}API_STD_FORMAT STREQUAL "AUTO"
+                                               AND NOT ${projectPrefix}LIB_FORMAT_SUPPORTED))
 )
     if(NOT TARGET fmt::fmt)
         find_package(fmt REQUIRED)