diff --git a/odxtools/compumethods/compumethod.py b/odxtools/compumethods/compumethod.py
index 9df65560..9abbe060 100644
--- a/odxtools/compumethods/compumethod.py
+++ b/odxtools/compumethods/compumethod.py
@@ -1,9 +1,9 @@
 # SPDX-License-Identifier: MIT
 import abc
 from dataclasses import dataclass
-from typing import Literal, Union
+from typing import List, Literal, Optional
 
-from ..odxtypes import DataType
+from ..odxtypes import AtomicOdxType, DataType
 
 CompuMethodCategory = Literal[
     "IDENTICAL",
@@ -24,17 +24,17 @@ class CompuMethod(abc.ABC):
     def category(self) -> CompuMethodCategory:
         pass
 
-    def convert_physical_to_internal(self, physical_value):
+    def convert_physical_to_internal(self, physical_value: AtomicOdxType) -> AtomicOdxType:
         raise NotImplementedError()
 
-    def convert_internal_to_physical(self, internal_value) -> Union[int, float, str]:
+    def convert_internal_to_physical(self, internal_value: AtomicOdxType) -> AtomicOdxType:
         raise NotImplementedError()
 
-    def is_valid_physical_value(self, physical_value):
+    def is_valid_physical_value(self, physical_value: AtomicOdxType) -> bool:
         raise NotImplementedError()
 
-    def is_valid_internal_value(self, internal_value):
+    def is_valid_internal_value(self, internal_value: AtomicOdxType) -> bool:
         raise NotImplementedError()
 
-    def get_valid_physical_values(self):
+    def get_valid_physical_values(self) -> Optional[List[DataType]]:
         return None
diff --git a/odxtools/compumethods/tabintpcompumethod.py b/odxtools/compumethods/tabintpcompumethod.py
index 0c6c2299..6be2b80b 100644
--- a/odxtools/compumethods/tabintpcompumethod.py
+++ b/odxtools/compumethods/tabintpcompumethod.py
@@ -3,7 +3,7 @@
 from typing import List, Tuple, Union
 
 from ..exceptions import DecodeError, EncodeError, odxassert, odxraise
-from ..odxtypes import DataType
+from ..odxtypes import AtomicOdxType, DataType
 from .compumethod import CompuMethod, CompuMethodCategory
 from .limit import IntervalType, Limit
 
@@ -115,7 +115,11 @@ def _piecewise_linear_interpolate(self, x: Union[int, float],
 
         return None
 
-    def convert_physical_to_internal(self, physical_value: Union[int, float]) -> Union[int, float]:
+    def convert_physical_to_internal(self, physical_value: AtomicOdxType) -> AtomicOdxType:
+        if not isinstance(physical_value, (int, float)):
+            raise EncodeError("The type of values of tab-intp compumethods must "
+                              "either int or float")
+
         reference_points = list(zip(self.physical_points, self.internal_points))
         result = self._piecewise_linear_interpolate(physical_value, reference_points)
 
@@ -127,7 +131,11 @@ def convert_physical_to_internal(self, physical_value: Union[int, float]) -> Uni
             odxraise()
         return res
 
-    def convert_internal_to_physical(self, internal_value: Union[int, float]) -> Union[int, float]:
+    def convert_internal_to_physical(self, internal_value: AtomicOdxType) -> AtomicOdxType:
+        if not isinstance(internal_value, (int, float)):
+            raise EncodeError("The internal type of values of tab-intp compumethods must "
+                              "either int or float")
+
         reference_points = list(zip(self.internal_points, self.physical_points))
         result = self._piecewise_linear_interpolate(internal_value, reference_points)
 
@@ -139,10 +147,16 @@ def convert_internal_to_physical(self, internal_value: Union[int, float]) -> Uni
             odxraise()
         return res
 
-    def is_valid_physical_value(self, physical_value: Union[int, float]) -> bool:
+    def is_valid_physical_value(self, physical_value: AtomicOdxType) -> bool:
+        if not isinstance(physical_value, (int, float)):
+            return False
+
         return min(self.physical_points) <= physical_value and physical_value <= max(
             self.physical_points)
 
-    def is_valid_internal_value(self, internal_value: Union[int, float]) -> bool:
+    def is_valid_internal_value(self, internal_value: AtomicOdxType) -> bool:
+        if not isinstance(internal_value, (int, float)):
+            return False
+
         return min(self.internal_points) <= internal_value and internal_value <= max(
             self.internal_points)
diff --git a/odxtools/parameterinfo.py b/odxtools/parameterinfo.py
index b3fe8575..210e400d 100644
--- a/odxtools/parameterinfo.py
+++ b/odxtools/parameterinfo.py
@@ -86,8 +86,8 @@ def parameter_info(param_list: Iterable[Union[Parameter, EndOfPduField]]) -> str
             ul = cm.physical_upper_limit
             result += (f" range: "
                        f"{'[' if ll.interval_type == IntervalType.CLOSED else '('}"
-                       f"{ll.value}, "
-                       f"{ul.value}"
+                       f"{ll.value!r}, "
+                       f"{ul.value!r}"
                        f"{']' if ul.interval_type == IntervalType.CLOSED else ')'}\n")
 
             unit = dop.unit