Phillipus....That explanation is not so simple either because Egypt continued to rule Canaan for many years AFTER the supposed time of the Exodus, so why should a less centralized governing by Egypt count (i.e. during the latter Middle Kingdom and Second Intermediate Period) but a much more imperialist and militarially enacted rule NOT count? It would work only if one adopts a very low chronology for the Exodus, not the high one advocated by the WTS and supported by certain chronographical texts in the OT (e.g. 1 Kings 6:1). A more serious problem is that the text in Exodus 12:40 clearly has the Israelites "dwelling in Egypt" (yshbw b-mtsrym) for 430 years, and that phrasing cannot be resolved by having part of that sojourn "in" Canaan. I know of know other text that refers to the land of Canaan as "Egypt". The two were always distinct.
Most scholars without an apologetic interest would simply recognize that the OT is an anthology of different works written (and redacted) at different times, and they simply attest different chronographical traditions about the Israelites.