Is the expiation for four hundred oaths considered as one single oath, or does each oath have its own individual expiation, in the case of repeated swearing with different intentions and varying amounts resulting from breaking the oath?

Frequent oath-taking is forbidden by Sharia. Allah Almighty has included the description of those who frequently take oaths among dispraised characteristics. As for repeated oaths concerning a single matter, the preponderant opinion is that there is only one expiation for breaking them. However, if there are multiple oaths concerning multiple matters, then the expiation multiplies with the multiplicity of the things sworn upon or about and the breaking of those oaths. The expiation for an oath is feeding ten poor people, or clothing them, or freeing a slave. If one cannot find these, then it is fasting for three days.