What one should know about Biblical Inerrancy

This is from the Chicago Statement on Biblical Inerrancy:

"C. Infallibility, Inerrancy, Interpretation
Holy Scripture, as the inspired Word of God witnessing authoritatively to Jesus Christ, may properly be called 'infallible' and 'inerrant'. These negative terms have a special value, for they explicitly safeguard crucial positive truths.
'Infallible' signifies the quality of neither misleading nor being misled and so safeguards in categorical terms the truth that Holy Scripture is a sure, safe and reliable rule and guide in all matters.
Similarly, 'inerrant' signifies the quality of being free from all falsehood or mistake and so safeguards the truth that Holy Scripture is entirely true and trustworthy in all its assertions.
We affirm that canonical Scripture should always be interpreted on the basis that it is infallible and inerrant. However, in determining what the God-taught writer is asserting in each passage, we must pay the most careful attention to its claims and character as a human production. In inspiration, God utilized the culture and conventions of his penman's milieu, a milieu that God controls in His sovereign providence; it is misinterpretation to imagine otherwise.
So history must be treated as history, poetry as poetry, hyperbole and metaphor as hyperbole and metaphor, generalization and approximation as what they are, and so forth. Differences between literary conventions in Bible times and in ours must also be observed: Since, for instance, nonchronological narration and imprecise citation were conventional and acceptable and violated no expectations in those days, we must not regard these things as faults when we find them in Bible writers. When total precision of a particular kind was not expected nor aimed at, it is no error not to have achieved it. Scripture is inerrant, not in the sense of being absolutely precise by modern standards, but in the sense of making good its claims and achieving that measure of focused truth at which its authors aimed.
The truthfulness of Scripture is not negated by the appearance in it of irregularities of grammar or spelling, phenomenal descriptions of nature, reports of false statements (for example, the lies of Satan), or seeming discrepancies between one passage and another. It is not right to set the so-called "phenomena" of Scripture against the teaching of Scripture about itself. Apparent inconsistencies should not be ignored. Solution of them, where this can be convincingly achieved, will encourage our faith, and where for the present no convincing solution is at hand we shall significantly honor God by trusting His assurance that His Word is true, despite these appearances, and by maintaining our confidence that one day they will be seen to have been illusions.
Inasmuch as all Scripture is the product of a single divine mind, interpretation must stay within the bounds of the analogy of Scripture and eschew hypotheses that would correct one Biblical passage by another, whether in the name of progressive revelation or of the imperfect enlightenment of the inspired writer's mind.
Although Holy Scripture is nowhere culture-bound in the sense that its teaching lacks universal validity, it is sometimes culturally conditioned by the customs and conventional views of a particular period, so that the application of its principles today calls for a different sort of action."

Personally, I think this disclaimer is extremely important. But I think the major ambiguity lies in the last 2 paragraphs. The holy scripture is certainly culturally bound. Why then do we eschew progressive revelation?