What it is
Shodashamsha divides each sign into sixteen equal parts of 1°52′30″. Here the starting point depends on the sign's nature: movable (Aries, Cancer, Libra, Capricorn), fixed (Taurus, Leo, Scorpio, Aquarius) or dual (Gemini, Virgo, Sagittarius, Pisces).
How it is calculated
Rule: in a movable sign the first part is Aries, in a fixed sign Leo, in a dual sign Sagittarius; then onward in order.
Example: a planet is at Aries 17°. 17 ÷ 1.875 ≈ 9.07, so the tenth part. Aries is movable, so the tenth sign from Aries: Capricorn. In D16 the planet is in Capricorn.
What tradition looks at in it
Parāśara links the shodashamsha to the joys and sorrows that come through vehicles. In today's language tradition treats it as the varga of comforts, ease and contentment. The lord of the 4th house and Venus, the traditional significator of comforts, are looked at here.
How much the birth time matters
On average the ascendant moves about 1 degree every 4 minutes; some signs rise faster, some slower. One part of D16 is 1°52′30″, so a difference of roughly 7–8 minutes in birth time can change the D16 ascendant. The Moon crosses one part in about three and a half hours. In your chart, ePandit shows next to every varga how many minutes of birth-time change would shift its ascendant. D16 and the higher vargas are not dependable without a reliable birth time.
How to read it calmly
Read D16 as a second look, not a verdict. Tradition first studies the 4th house and its lord in the main chart (D1), then the running dasha. D16 only helps check whether the same theme shows up here as well. A planet's sign in this varga decides nothing on its own. Contentment often comes from small things and relationships; this varga does not measure it, it only speaks about it in tradition's language.