Those numbers exemplify the misinformation which is prevalent in the users world of batteries. Let us first open our eyes in the use of various terms. "lead-acid" does not denote flooded-cell constructed batteries only. Lead-acid denotes battery chemistry of which gel-cel, AGM and flooded-cell constructed batteries form sub-groups. Regardless of the subgroup the electrochemistry is essentially the same. Differences vary little with regard to those designed to be used in deep-discharge high current
The three-step charging regimen was developed and proposed as an approximation to the Amp-hour charging "law", a textbook documentation
from the 1930's which was not popularized until David Smead, and Rick Proctor of Cruising Equipment
Co (yes, at one time Dave Smead worked with Proctor before forming his Ample Power
company) insisted on proper technical references
rather than promulgating the usual "what my father did seemed to work" kinda pseudotechnology.
As a result of the misinformation which is prevalent even within the battery distributors of various manufacturers there is no uniform agreed upon set of acceptance and float voltage values across the manufacturing board.
Battery electrochemists, few as they are, are the ultimate source of "real" information which is why I, along with few others, refer only to the authoritative electrochemistry textbooks and technical publications. The fact that battery distributors must print some information which is in keeping with what available product chargers are capable of delivering helps limit their exposure to having to make "good" on battery warranty contracts.
Over several decades I, and others, have verified that indeed the gel-cel and AGM batteries still benefit from that old Amp-hour law charging which the 3-step charging regimen approximates. The two fundamental reasons for varying particular voltage limits for acceptance and float values are temperature (well defined) and specific gravity. Regardless, if the Amp-hour "law" is followed by using a battery monitor
that is capable of measuring accurately Amp-hours in and out the deviation of acceptance voltage is allowed without penalty.
In conjunction with having utilized a sufficiently high acceptance voltage the charge acceptance of a fully charge battery will be very low and it has been observed that the slight variation of float voltage will therefore, result in little current change and certainly not so as to gas the battery as long as radical temperature changes (greater than 10 deg F, for example) are noticed in order to adjust the float voltage.