diff --git a/_sections/30-bindings.md b/_sections/30-bindings.md
index 521eebf..adb2fbc 100644
--- a/_sections/30-bindings.md
+++ b/_sections/30-bindings.md
@@ -39,7 +39,7 @@ The following attributes are supported on `<bind>` nodes. Only the nodeset attri
 | `required`  | As in [XForms 1.0](https://www.w3.org/TR/2003/REC-xforms-20031014/slice6.html#model-prop-required) this pecifies whether the question requires a non-empty value, using a boolean expression. Considered `false()` if omitted.
 | `relevant`  | As in [XForms 1.0](https://www.w3.org/TR/2003/REC-xforms-20031014/slice6.html#model-prop-relevant) this specifies whether the question or group is relevant. The question or group will only be presented to the user when the XPath expression evaluates to `true()`. When `false()` the data node (and its descendants) are removed from the primary instance on submission.
 | `constraint`| As in [XForms 1.0](https://www.w3.org/TR/2003/REC-xforms-20031014/slice6.html#model-prop-relevant) this specifies acceptable answers for the specified prompt with an XPath expression. Will only be evaluated when the node is non-empty.
-| `calculate` | As in [Xforms 1.0](https://www.w3.org/TR/2003/REC-xforms-20031014/slice6.html#model-prop-calculate) this calculates a node value with an XPath expression.
+| `calculate` | As in [Xforms 1.0](https://www.w3.org/TR/2003/REC-xforms-20031014/slice6.html#model-prop-calculate) this calculates a node value with an XPath expression. Calculation is performed at the time of Form load, Form save, Form submission, and when the values of dependent nodesets are changed. If the corresponding nodeset is editable, the user-provided value will never be saved or submitted.
 | `saveIncomplete` | Specifies whether to automatically save the draft record when the user reaches this question, options `true()` and `false()`. Considered false() if omitted.
 | `jr:requiredMsg` | Specifies the custom message to be displayed when the `required` is violated. Value can be string literal (`jr:constraintMsg="message"`) or a [translation function](#fn:Translation-Functions) call (`jr:constraintMsg="jr:itext('id')"`).
 | `jr:constraintMsg` | Specifies the custom message to be displayed when the `constraint` is violated. Value can be string literal (`jr:requiredMsg="message"`) or a [translation function](#fn:Translation-Functions) call (`jr:requiredMsg="jr:itext('id')"`).