My natural reaction is to start reviewing right away, and keep at it until I remember them all again. However, this is not recommended. On the website of Supermemo, the original (and best?), there is an explicit warning against reviewing too early. Remembering early does not translate into remembering well, they say. Spacing the repetition makes the brain store it more permanently. Besides, the software will correct itself: If it finds that I have forgotten too much, it will have a shorter wait next time (than it otherwise would).
On the other hand, the starting value is probably calibrated for the usual type of learning: "Under what tree did Gautama become the Buddha?" "In what year did the Dalai Lama receive Nobel's Peace Prize?" "What does the word 'nirvana' mean?" For a verbally oriented person, such questions are trivially easy compared to staring at a random visual pattern and associate it with a random sound. A week may be about right to begin forgetting a word or a number. For hiragana, a week would be a complete team wipe. The memories would not only be dead but decomposed and converted into daisies.
Why oh why was I born into a race of idiots, and stayed that way? Why wasn't I at least raised by Martians?