Chart ten requires an explanation. There are 3 charts on the page. The top chart is a full cycle and should present no special problem. The two bottom charts are in reality one cycle interrupted by breakthrough bleeding. The point of the CCL exercise is to train the chartist to recognize breakthrough bleeding and not make the mistake of thinking there are two cycles instead of only one. Obviously any fertility software should also recognize the same reality and keep the woman out of trouble when she is postponing pregnancy.

Chart Ten Test (top chart)

	Phase 2 Starts on	Phase 3 Starts on	Next Cycle Starts on	Total Days Difference in Cycle from CCL
Fertility Monitor	Day 9	Day 18	Day 27	Zero
CCL	Day 9	Day 18	Day 27	Zero
Life Cycle's Fertility Predictor	Day 4	Day 18	Day 27	-5

Chart Ten Test (middle chart and bottom chart)

	Phase 2 Starts on	Phase 3 Starts on	Next Cycle Starts on	Total Days Difference in Cycle from CCL
Fertility Monitor	Day 7	Day 43	Day 47	-4
CCL	Day 7	Day 39	Day 47	Zero
Life Cycle's Fertility Predictor	Day 4 Day 4	Never Day 10	Day 30 Day 18	-3 -3

The Life Cycle software is fooled by the breakthrough bleeding and divides this one cycle into two. It allows coitus on days 30 through 32 of the actual cycle. This is bad news because the woman is trying to avoid pregnancy and day 30 through 32 is a fertile time. Curiously the Life Cycle software asks the user, in a message, to distinguish between menstruation and spotting/breakthrough bleeding on what it thinks is day 18 of the pseudo cycle. The question might better have been asked on day 30 of the real cycle.

The four day error of the Fertility Monitor in this difficult chart is on the conservative side. That is to say being late to phase three would not result in an unintended pregnancy. It was caused by the lack of mucus observations on days 30 through 31 which invoked a late temperature only interpretation.

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